KYIV, Ukraine — In the final days before the invasion of Ukraine, Russia’s security service began sending cryptic instructions to informants in Kyiv. Pack up and get out of the capital, the Kremlin collaborators were told, but leave behind the keys to your homes.

The directions came from senior officers in a unit of Russia’s Federal Security Service (FSB) with a prosaic name — the Department of Operational Information — but an ominous assignment: ensure the decapitation of the Ukrainian government and oversee the installation of a pro-Russian regime.

The messages were a measure of the confidence in that audacious plan. So certain were FSB operatives that they would soon control the levers of power in Kyiv, according to Ukrainian and Western security officials, that they spent the waning days before the war arranging safe houses or accommodations in informants’ apartments and other locations for the planned influx of personnel.

“Have a successful trip!” one FSB officer told another who was being sent to oversee the expected occupation, according to intercepted communications. There is no indication that the recipient ever made it to the capital, as the FSB’s plans collapsed amid the retreat of Russian forces in the early months of the war.

The communications exposing these preparations are part of a larger trove of sensitive materials obtained by Ukrainian and other security services and reviewed by The Washington Post. They offer rare insight into the activities of the FSB — a sprawling service that bears enormous responsibility for the failed Russian war plan and the hubris that propelled it.

An agency whose domain includes internal security in Russia as well as espionage in the former Soviet states, the FSB has spent decades spying on Ukraine, attempting to co-opt its institutions, paying off officials and working to impede any perceived drift toward the West. No aspect of the FSB’s intelligence mission outside Russia was more important than burrowing into all levels of Ukrainian society.

And yet, the agency failed to incapacitate Ukraine’s government, foment any semblance of a pro-Russian groundswell or interrupt President Volodymyr Zelensky’s hold on power. Its analysts either did not fathom how forcefully Ukraine would respond, Ukrainian and Western officials said, or did understand but couldn’t or wouldn’t convey such sober assessments to Russian President Vladimir Putin.

[Hubris and isolation led Vladimir Putin to misjudge Ukraine]

The humiliations of Russia’s military have largely overshadowed the failures of the FSB and other intelligence agencies. But in some ways, these have been even more incomprehensible and consequential, officials said, underpinning nearly every Kremlin war decision.

“The Russians were wrong by a mile,” said a senior U.S. official with regular access to classified intelligence on Russia and its security services. “They set up an entire war effort to seize strategic objectives that were beyond their means,” the official said. “Russia’s mistake was really fundamental and strategic.”

Ukraine’s security services have an interest in discrediting Russia’s spy agencies, but key details from the trove were corroborated by officials in Western governments.

The files show that the FSB unit responsible for Ukraine surged in size in the months leading up to the war and was counting on support from a vast network of paid agents in Ukraine’s security apparatus. Some complied and sabotaged Ukraine’s defenses, officials said, while others appear to have pocketed their FSB payments but balked at doing the Kremlin’s bidding when the fighting started.

There are records that add to the mystery of Russian miscalculations. Extensive polls conducted for the FSB show that large segments of Ukraine’s population were prepared to resist Russian encroachment, and that any expectation that Russian forces would be greeted as liberators was unfounded. Even so, officials said, the FSB continued to feed the Kremlin rosy assessments that Ukraine’s masses would welcome the arrival of Russia’s military and the restoration of Moscow-friendly rule.

“There was plenty of wishful thinking in the GRU and the military, but it started with the FSB,” said a senior Western security official, using the GRU abbreviation for Russia’s main military intelligence agency. “The sense that there would be flowers strewn in their path — that was an FSB exercise.” He and other security officials in Ukraine, the United States and Europe spoke on the condition of anonymity to discuss sensitive intelligence.

Adhering to these erroneous assumptions, officials said, the FSB championed a war plan premised on the idea that a lightning assault on Kyiv would topple the government in a matter of days. Zelensky would be dead, captured or in exile, creating a political vacuum for FSB agents to fill.

Instead, FSB operatives who at one point had reached the outskirts of Kyiv had to retreat alongside Russian forces, Ukrainian security officials said. Rather than presiding over the formation of a new government in Kyiv, officials said, the FSB now faces difficult questions in Moscow about what its long history of operations against Ukraine — and the large sums that financed them — accomplished.

The FSB did not respond to requests for comment.

The FSB’s plans and the efforts of Ukraine’s security agencies to thwart them — with backing from the CIA, Britain’s MI6 and other Western intelligence services — are part of a shadow war that has played out in parallel to Russia’s military campaign. It is a conflict that was underway long before the Feb. 24 invasion, and its battle lines are blurred by the tangled, overlapping histories of Russian services and Ukrainian counterparts that began as offspring of the Soviet-era KGB.

Six months into the war, neither side appears to have a clear upper hand.

Ukraine’s security agencies have scored notable victories. Early on, a Ukrainian nongovernmental organization published what it described as a roster of FSB operatives linked to the war effort, posting the identities and passport numbers of dozens of alleged spies in a move meant to disrupt the agency’s plans and rattle its personnel. A person connected to the NGO, which is called Myrotvorets, or Peacemaker, said the data was obtained by Ukraine’s security services. The person spoke on the condition of anonymity, citing threats to his security.

At the same time, Ukraine’s main internal security service, the SBU, has struggled to rid its ranks of Russian moles and saboteurs. Several senior officers have been arrested and branded traitors by Zelensky, who took the extraordinary step in July of removing SBU Director Ivan Bakanov — a childhood friend — from his post.

Putin is not believed to have taken comparable action against any of his spy chiefs, despite the scale of their misjudgments.

“If your security services put such a high priority on understanding Ukraine, and your military plan is based on that understanding, how could they have gotten it so wrong?” said William B. Taylor Jr., who twice served as U.S. ambassador to Ukraine, including in an acting capacity in 2019. “How could they have assumed the Ukrainians wouldn’t fight, that President Zelensky would not resist so valiantly? The disconnect has to be somewhere between the FSB and the very top.”

II

Among those making plans to arrive in Kyiv in late February was Igor Kovalenko, identified by Ukraine as a senior FSB officer who had for years been a principal handler of some of the most prominent Ukrainian politicians and government officials secretly on the Kremlin’s payroll, including members of the opposition party co-chaired by Viktor Medvedchuk, a close friend of Putin.

An exchange Kovalenko had with an FSB subordinate on Feb. 18 suggests that he had his eye on an apartment in Kyiv’s leafy Obolon neighborhood, overlooking the Dnieper River.

Intercepted communications show that Kovalenko asked for the address of the apartment and contact details for an FSB informant who occupied it. Ukrainian authorities said the resident was subsequently detained and questioned.

Kovalenko’s subordinate sent back the address, phone numbers and code words used to communicate with the informant, who served in Zelensky’s government, Ukrainian officials said.

The officials declined to identify the informant but said he admitted that he had received FSB instructions days before the invasion to pack his belongings, leave his keys and get out of the capital to ensure his personal security during the war’s initial phase.

Other informants detained by Ukrainian authorities have provided similar accounts, one of the officials said. “They had been told, ‘When you return, it will all be different.’ ”

Details published by Peacemaker and confirmed by Ukrainian security officials describe Kovalenko as a 47-year-old veteran of the spy service who in recent years was responsible for managing the agency’s clandestine ties to Ukraine’s parliament and main pro-Russian party.

Kovalenko did not respond to requests for comment.

Ukrainian authorities believe that Kovalenko may have been just miles from the capital in March, accompanying Russian forces then outside the city. But the FSB team assigned to set up operations in Kyiv had to abandon that plan when Russia’s forces began their retreat, officials said.

The Obolon apartment was placed under surveillance by the SBU after the address surfaced in communications intercepts, officials said. Neither Kovalenko nor any other FSB officer ever turned up to claim the keys.

III

Kovalenko is a senior officer in an FSB unit — the Ninth Directorate of the Department of Operational Information — whose main purpose has for years been to ensure Ukraine’s servility to Moscow.

The department is overseen by a senior FSB officer, Sergey Beseda, who started his career with the KGB in the late 1970s, according to Ukrainian officials, and was assigned to overseas posts including Cuba before returning to Moscow to head operations in Ukraine, Georgia and other former Soviet republics.

After protests erupted in Kyiv in late 2013 against the pro-Russian government of Viktor Yanukovych, Beseda turned up in the Ukrainian capital urging Yanukovych to use deadly force to put down an uprising that would come to be known as the Maidan Revolution, Ukrainian officials said.

When the protesters prevailed, Yanukovych fled to Russia with a group of senior advisers suspected of working with Beseda’s branch in the years that followed to bring a pro-Russian government back to power.

That project appeared to take on new urgency in the two years leading up to the February invasion.

In 2019, the FSB began a major expansion of its Ukraine unit, a group that grew from 30 officers to as many as 160 last summer, according to Ukrainian officials who cited intercepted communications and other intelligence.

To entice recruits from other branches, the FSB offered bonuses and free housing in buildings adjacent to the FSB training academy on Michurinsky Prospekt in Moscow, officials said. Arriving officers were assigned territories in Ukraine and tasked with developing lists of collaborators to work with, as well as adversaries to neutralize.

[In Ukrainian villages, whispers of collaboration with the Russians]

At first, the surge was seen as another venture aimed at “returning Russian influence in Ukraine,” said a security official in Kyiv involved in tracking FSB operations. But in retrospect, it may have been an early signal that Russia was shifting focus, the official said, from shaping events in Ukraine to plotting “its seizure.”

As Russia’s military mobilization accelerated last year, Ukraine’s security services were inundated with additional intelligence from Western spy services, officials said.

On Jan. 12, CIA Director William J. Burns arrived in Kyiv with a detailed dossier on Russia’s plans and a team of accompanying U.S. officials who sought to convince Zelensky and his inner circle that war was imminent.

Yet when the CIA team departed, Ukraine’s spy chiefs gathered with Zelensky to deliver a follow-on briefing that was far more equivocal.

“We relayed all the information that the Americans had shared without any changes,” said a participant. But at the same time, the official said, “our information said that the Russians are not planning war” on such a large scale, and that judgment was given equal weight alongside the CIA warnings.

The final weeks before the invasion were punctuated by a flurry of contradictory intelligence reports and confusing signals from European officials.

Ten days after Burns’s visit, the British government declared that it had “information that indicates the Russian government is looking to install a pro-Russian leader in Kyiv as it considers whether to invade and occupy Ukraine.”

The British file identified a pro-Russian former member of Ukraine’s parliament, Yevhen Murayev, “as a potential candidate,” a claim that Murayev dismissed as “ridiculous and funny” in a response to the Associated Press. The British statement also listed former members of Yanukovych’s cabinet, alleging that they had links to Russian intelligence and that officers they were in contact with were “involved in the planning for an attack on Ukraine.”

About the same time, Ukraine’s security agencies picked up indications that FSB operatives were in direct communication with Russia’s airborne forces, officials said. Such direct interaction between the FSB and military units was so unusual, officials said, that it was regarded as a worrisome sign of joint operational planning.

[The man who has Putin’s ear — and may want his job]

That concern seems to have been well-placed. Russia’s airborne forces played a pivotal role in the capture of an airport in Hostomel, on the outskirts of Kyiv, in the early hours of the invasion. It was a key node for the anticipated assault on the capital, and FSB officers were observed there before Russian forces were driven from the airstrip, officials said.

Other late-arriving intelligence, however, seemed to cast doubt on the idea that Russia was even prepared for, let alone planning, full-scale combat.

In mid-February, Ukraine’s foreign intelligence service, the SZR, sent agents into Russia to carry out surveillance operations on military units. One team encountered a Potemkin village of Russian hardware, officials said, with dozens of parked tanks accompanied by a small security detail. No tank operators or maintenance crews were anywhere in the vicinity.

Elsewhere, Ukraine’s spies came upon a scene of disciplinary mayhem: lines of stranded Russian vehicles accompanied by troops who had bartered fuel and other supplies for alcohol. “A lot of them were drunk,” said a Ukrainian official who reviewed reports on what Ukraine’s spies had witnessed.

The scenes fed doubts among security advisers to Zelensky, some of whom were understandably disinclined to believe that their country’s days might be numbered. Even now, months later, many continue to express disbelief that Russia pressed ahead so poorly prepared.

European officials also remained skeptical. In Kyiv on Feb. 8, French President Emmanuel Macron said he had received a personal assurance from Putin that Russia would not escalate the situation. Germany’s spy chief, Bruno Kahl, had said days earlier that Putin’s decision on whether to attack had “not yet been made.” (Kahl was in Kyiv on the day the invasion began and had to be evacuated by car to Poland.)

In the end, many Ukrainian security officials believed that Russia’s military buildup was largely a psychological ploy, but that Moscow might use missile strikes and incursions by airborne units and elite Spetsnaz troops to topple a government it saw as teetering. At the time, Zelensky’s approval ratings had plummeted to around 26 percent as Ukraine faced an energy crisis and pressure on its currency that officials attributed to Russian sabotage.

“We didn’t envision … some classic invasion in Second World War style with tanks, artillery and infantry,” a senior Ukrainian security official said. Ukraine was wrong about Russia’s intentions, he said, but even Moscow may not have envisioned a major land war.

“They expected somebody to open the gate,” the official said. “They didn’t expect any resistance.”

In an interview this month with The Post, Zelensky said that well before the invasion, Russia had been waging “a hybrid war against our state. There was an energy blow, there was a political blow.”

“They wanted a change of power from inside the country,” he said. “I had the feeling that [the Russians] wanted to prepare us for a soft surrender.”

IV

Ukraine’s SBU — like its Russian counterpart — is a direct descendant of the KGB. It occupies the former KGB headquarters in Kyiv, is organized around the same bureaucratic structure as its Soviet predecessor, and employs an undisclosed number of officers who trained at the KGB academy in Moscow or its FSB successor after the Soviet breakup.

The agencies’ entangled histories bring a hall-of-mirrors aspect to the conflict.

Current and former Ukrainian security officials said fear about the loyalties of even senior personnel is a source of constant anxiety. One official said he reached for his phone on the war’s second day to begin calling subordinates to relay orders. But he hesitated as he dialed, he said, worried that his calls would go unanswered or reveal that senior lieutenants had thrown their support to the Russians.

He was stunned, he said, when those he called not only answered but followed orders with a precision and determination that were rare before the conflict.

“It’s a paradox of the Ukrainian state,” the official said. “It was believed, including by Ukrainians themselves, that there was a high level of corruption, inefficiency and infiltration of Russian agents in the Ukrainian government structures.” But after Feb. 24, he said, “they not only worked but also worked more efficiently than ever.”

He and others attributed much of that resilience to the example Zelensky set with his decision to remain in the capital. His ability to do so was due in part to the existence of a massive bunker complex under Kyiv’s government quarter that was designed by Soviet engineers and built to survive nuclear conflict.

A senior adviser described being taken to meet Zelensky in the first weeks of the war and descending into a disorienting warren of tunnels and command posts. “I still can’t say to you where [Zelensky’s base of operations] is exactly,” he said, because the complex is such a labyrinth.

Ukraine has made repeated attempts to cleanse its ranks of Russian assets, at one point even enlisting a CIA officer to serve as an internal adviser on rooting out FSB penetrations, according to former U.S. officials. But with an estimated 27,000 employees — making the SBU at least five times as large as MI5, its British equivalent — the agency has struggled to surmount the problem.

“Is there treachery? What can I say?” Zelensky said. “With all my love for Ukraine, we are not without sin.” The number of those who are not loyal to their country “has fallen over the years,” he said. Still, when the war started, “there were people who were working for Russians for money, and some who from the inside always hated Ukraine and were waiting for the Soviet Union to return.”

Several senior SBU officers have been charged with treason. Among them is the former head of the agency’s directorate in Kherson, in southern Ukraine, who was accused of ordering subordinates to abandon their posts as Russian forces flooded the region.

[In Kherson, misery under Russian occupation, hope over Ukrainian gains]

Last month, Ukrainian authorities arrested another SBU officer, Oleg Kulinich, who had been installed in the service’s upper ranks by Bakanov, the SBU director and childhood friend of Zelensky. The allegations against Kulinich underscore the pervasiveness of Russian penetrations. Charges filed by Ukrainian authorities describe him as part of a cell of sleeper agents operated by Vladimir Sivkovich, a former deputy head of Ukraine’s security council who was placed under sanction by the U.S. Treasury Department in January for working “with a network of Russian intelligence actors to carry out influence operations.”

Two years before the war, Sivkovich “set a task for Kulinich” to begin stealing secret internal SBU files that would be “of operational interest” to the “special services of the Russian Federation,” according to the charging document.

Together, according to the document, they conspired to help promote another alleged Russian spy to take control of the SBU’s counterintelligence department. That figure, Andriy Naumov, was arrested in Serbia in June carrying cash and gems worth more than $700,000, according to information released by Serbian authorities.

On the night before Russia’s invasion, Kulinich “deliberately” blocked the dissemination of intelligence warning that Russian forces in Crimea were hours from launching an attack, according to the Ukrainian indictment.

Zelensky’s decision to oust Bakanov as SBU director after Kulinich’s arrest was driven by exasperation with his failure to “cleanse” the agency of Russia sympathizers, said Andriy Smirnov, deputy head of Ukraine’s presidential office. “Six months into the war,” he said, “we continue to uncover loads of these people.”

Bakanov did not respond to requests for comment. Kulinich, Sivkovich and Naumov could not be reached for comment, and none appears to have made any public statement about the allegations against them.

Overall, Ukraine has detained more than 800 people suspected of aiding Russia through reconnaissance or sabotage, according to Ukraine’s Interior Ministry. Authorities have also moved against suspected “agents of influence” in government, parliament and politics.

Chief among them is Medvedchuk, the opposition party chairman who has such close ties to Putin that the Russian leader is the godfather of his youngest daughter. Ukrainian officials described Medvedchuk, 68, as a savvy political operator who harbored ambitions of high office himself and probably would have served as puppet-master to any regime installed by the Kremlin.

Zelensky’s government had charged Medvedchuk with treason in May 2021 and placed him under house arrest. Medvedchuk denied any wrongdoing and said he would fight to clear his name. He then escaped during the early days of the war, but was recaptured in April and now awaits trial. Medvedchuk’s lawyer, Tetyana Zhukovska, declined to comment this month, saying she could not do so until a Ukrainian court ruled in the treason case against her client.

[In the Ukraine war, a battle for the nation’s mineral and energy wealth]

“When they began on Feb. 24, the task was to take Kyiv,” said a Ukrainian security official. “They expected it would lead to a domino effect” that would ripple across the country. “They would take first central power and then they would have strengthened presence in regions.”

As part of that plan, Ukrainian officials said, the FSB had lined up at least two pro-Russian governments-in-waiting — not just one as the British government had warned. Ukraine officials said it was unclear why Russia had mobilized two groups, though some speculated that Putin may have simply wanted options.

One, positioned in Belarus, centered on Yanukovych. On March 7, a plane that belonged to the former Ukrainian president landed in Minsk, its arrival treated as an indication that Russia might seek to reinstate a politician Kremlin officials still referred to after his 2014 ouster as the country’s “legitimate” leader.

Yanukovych then issued an open letter to Zelensky, broadcast by a Russian state news agency, in which he told the Ukrainian president it was his duty to “stop the bloodshed and reach a peace deal at any price.” Over the following week, Yanukovych’s security chief spoke three times with a senior officer from the FSB’s Ukraine unit, according to data intercepted by Ukrainian intelligence.

Yanukovych did not respond to requests for comment. His former prime minister, Nikolai Azarov, said in a telephone interview with The Post that any suggestion that Moscow was seeking to engineer Yanukovych’s return to power was “total nonsense.”

A second group, which included former members of the Yanukovych government, gathered in southeastern Ukraine as territory there fell to Russian forces. Among them was Oleg Tsaryov, a former leading member of Yanukovych’s Party of Regions, who declared his presence in Ukraine on a post to the Telegram messaging app, saying that “Kyiv will be free from fascists.”

In a telephone interview with The Post last month, Tsaryov said he had even moved into areas around Kyiv during the initial weeks of the war, traveling with “friends” he declined to identify. He wouldn’t answer questions about whether he was part of any plot to seize power, saying only that when he was outside Kyiv, “I didn’t have any agreements with anyone about a new government.”

V

Nearly every intelligence service with a stake in the war made consequential misjudgments.

U.S. spy agencies were prescient on Putin’s intentions but underestimated Ukraine’s ability to withstand the onslaught — an error that contributed to the United States’ initial hesitation to send heavy and sophisticated weapons.

Ukraine’s services appear to have read too much into signs that Russian forces were ill-prepared for full-scale combat, resisting Western warnings of an invasion that came within miles of the capital.

Russia’s intelligence breakdowns in Ukraine seem more systemic, its work marred by unreliable sources, disincentives to deliver hard truths to the Kremlin, and an endemic bias that matched Putin’s contemptuous attitude toward the country.

The FSB fueled this dynamic, officials said, with assessments packaged to please the Kremlin and with sources who had their own reasons — political and financial — for encouraging a Russian takedown of the Kyiv government.

Confidential reports by a think tank with close ties to the FSB, the Moscow-based Institute of CIS Countries, prodded Moscow to reassert control over its neighbor. An early 2021 report obtained by The Post said that doing so was the only way to “rid Russia of the eternal threat … posed by the puppet state ready to carry out any order of the enemy forces of the West.”

The director of the institute, Konstantin Zatulin, insisted in a telephone interview that he had opposed the use of military force against Ukraine, and blamed the Kremlin’s “inflated expectations” about what the invasion could accomplish on exaggerations by Kremlin allies in the country.

Foremost among them was Medvedchuk, who had served as presidential chief of staff in the early 2000s before amassing a business fortune and becoming co-leader of Ukraine’s main pro-Russian party.

Unlike other Ukrainian figures, Medvedchuk was in direct contact with Putin, according to officials who cited monitored communications. His was the most prominent voice in a chorus of Kremlin allies assuring Moscow that Zelensky was weak, that his government would collapse and that Russian forces would be welcomed by the Ukrainian people, officials said.

In recent years, Medvedchuk appeared to use his business empire to lay the groundwork for a Russian move against Kyiv. His TV stations routinely bashed Zelensky and aired pro-Russian propaganda, including discredited claims that the United States had biolabs in the country to help Ukraine develop biological weapons. His companies, which included a stake in an oil refinery in southern Russia, served as a conduit for money that flowed to pro-Russian forces and backed plots to destabilize the Kyiv government, officials said.

As his activities became more brazen, the United States and Ukraine moved against his network.

The U.S. Treasury Department, which had previously placed Medvedchuk under sanction, went after key party lieutenants in January, accusing them of collaborating with Russian intelligence on efforts to “take over the Ukrainian government and control Ukraine’s critical infrastructure with an occupying force.”

One of those sanctioned associates, Oleh Voloshyn, denied that he or Medvedchuk had any specific prior knowledge of Russia’s invasion plan or that they were seeking to overthrow the Zelensky government. In a telephone interview with The Post last month, Voloshyn blamed the war on Zelensky, saying the repression of Medvedchuk and his supporters forced Moscow to defend its allies.

“The choice was always becoming neutral voluntarily, or made neutral through force,” he said. “I don’t say this is good or bad. It’s just the reality.”

Almost immediately, the war failed to live up to Medvedchuk’s forecasts. And it was his political network, rather than Zelensky’s, that ultimately folded, with as many as a dozen senior party officials leaving the country.

Moscow’s subsequent spurning of Medvedchuk has been one of the few visible signs of Putin’s pique.

After Medvedchuk was recaptured in mid-April, Ukrainian authorities proposed sending him to Moscow as part of a prisoner swap. But officials said the Kremlin has shown no interest in any deal that would free the oligarch.

Often pictured before the war wearing immaculately tailored suits in meetings with the Russian leader, recent images released by Ukraine show Medvedchuk in prison fatigues and handcuffs.

To the Kremlin, “he is a traitor because he took all the money and delivered no results,” said Kostyantyn Batozsky, who was an adviser to a Donetsk governor before the region was taken over by pro-Russian separatists.

Medvedchuk “is a played card; they will never use him again,” Batozsky said. “He doesn’t want to go to Russia now because he will be asked the most unpleasant question in the world: What about the money? Where did it go?”

VI

One of the more puzzling aspects of Russia’s miscalculation is that the FSB had received information suggesting that war with Ukraine would not be a walkover.

Recent polls conducted by an organization with close ties to the FSB showed that Putin was deeply unpopular in Ukraine and that the idea that Russian forces would be welcomed was fiction, according to copies obtained by Ukrainian intelligence.

An April 2021 poll by the firm Research & Branding found that 84 percent of Ukrainians would regard any further encroachment by Russian forces as an “occupation,” with just 2 percent seeing such a scenario as a “liberation.”

A second poll, conducted in late January just weeks before the war, queried Ukrainians about invasion scenarios in extraordinary detail, according to a 26-page document reviewed by The Post. It was commissioned by and presented to Sivkovich, the former Yanukovich aide who is accused of running sleeper agents, Ukrainian officials said.

Was a “great war” between the countries possible? the poll asked. Were people “feeling concerned for themselves and their loved ones” about the buildup of Russian forces? Was Ukraine’s army capable of fending off an invasion?

The most salient question appears toward the end of the poll: “Are you ready to defend Ukraine in the event of such a necessity?” Overall, 48 percent answered in the affirmative.

Ukrainian officials said the number should have been interpreted as a sign of resolve, showing that millions of citizens were ready to take up arms against Russia. The FSB, however, may have drawn a different conclusion from the same data, believing that only a minority of Ukrainians were committed to defending their country.

It is unclear whether the results of these surveys were accurately relayed to the Kremlin.

When contacted by telephone, Eduard Zolotukhin, Research & Branding’s director, asked The Post to send written questions, but then did not respond.

VII

The fallout for the FSB has been difficult to ascertain amid the information blackout imposed on Russian media by Putin.

Early reports that Beseda, responsible for the FSB’s Ukraine directorate, had been demoted or even imprisoned are viewed skeptically by U.S. and other intelligence officials, who say they have seen no information to suggest that any of Russia’s spy chiefs has faced such consequences.

“We have pretty good reason to believe that he’s still in the job,” a senior U.S. official said of Beseda. Nor, the official said, is there any indication that FSB chief Alexander Bortnikov has been held to account for his agency’s failures. A senior Russian politician with close links to the Kremlin and to the FSB also said in an interview that Beseda was continuing to carry out his duties.

[The West has imposed a barrage of sanctions on top Russian figures. See how they’re connected to Putin.]

Other reports indicated that Putin had sidelined the FSB because of its failures and given greater responsibility for Ukraine to the military-linked GRU. Ukrainian officials say otherwise.

“I don’t share this view,” one official said. The FSB “didn’t manage the task they were given. But they are continuing to work. Not with the same enthusiasm. But they continue.”

Ukrainian officials cited recent intelligence indicating that the FSB — like the Russian military — has regrouped, turning its focus to territories in the south and east that have been obliterated by Russian artillery.

“We can see it playing out now in Mariupol, Melitopol, Kherson” and other cities that have fallen to Russian forces, a Ukrainian intelligence official said. FSB officials swoop in to implement a version of the blueprint the agency originally had for Kyiv.

“The aim is political control, economic control, control over criminal groups — all spheres of activity on seized territory,” the intelligence official said. “The final aim is to install a pro-Russian power.”

Kherson, the first major city to fall to the Russian army, now offers a chilling glimpse into what life might have been like if Russia had taken Ukraine’s capital.

The city’s mayor, Ihor Kolykhaiev, was arrested in June after repeatedly refusing to cooperate with the Russian occupiers, and his whereabouts are unknown, an aide to the mayor said. He has been replaced by Oleksandr Kobets, a former KGB officer who had also once worked for the SBU.

The former mayor’s aide, Galina Lyashevskaya, said that at least 300 residents were unaccounted for when Kolykhaiev was ousted from his position in April. More recent estimates are at least double that.

Many more have been arrested, she said, and about half the city’s population of 300,000 has fled. In a recent report, Human Rights Watch documented dozens of cases of torture among Kherson’s residents.

“The FSB does not have any uniform, so you never know who is standing next to you,” Lyashevskaya said. “It is paradise for the FSB here. … They can force anyone to do what they want.”

Ukrainian officials said the FSB is involved in planning a referendum that would provide a pretext for incorporating the city and surrounding region into Russia. But Ukraine has begun staging forces for a major counteroffensive to retake Kherson.

VIII

With no end to the war in sight, FSB officials have begun operating on three-month rotations, according to Ukrainian security officials.

Kovalenko, the FSB operative who had inquired about a riverside apartment in Kyiv, retreated to Russia with a broken finger and apparent unease about Ukrainian penetrations of his directorate, according to Ukrainian security officials. In communications with relatives that were monitored by Ukrainian intelligence, he spoke about changing phones, switching addresses in Moscow and even selling family vehicles. Then, in late May, he revealed that he was being sent back to Ukraine for another assignment.

One relative responded to the news with a Russian expletive.

Ukrainian officials said they have not been able to determine Kovalenko’s current whereabouts.

Shane Harris, Karen DeYoung and Souad Mekhennet in Washington and Isabelle Khurshudyan and David L. Stern in Kyiv contributed to this report.