“Today there is no connection, the station management works at invaders’ gunpoint,” Kotin continued.

“As for the staff, they were admitted in the morning to perform their duties. We do not currently have a direct connection to the station. We get information from the sources at the station.”

Kotin warned that although the reactors are safe, further attacks could lead to “disaster.”

Ukraine’s State Emergency Services (SES) had earlier confirmed several dozen firefighters had extinguished a blaze that had started in a training building outside the main reactor complex, following shelling from Russian military forces.

Reports of the fire raised concern from world leaders and the International Atomic Energy Agency (IAEA) — who called for a stop to fighting around the facility — though the IAEA said Ukrainian authorities had reported background radiation levels were normal and the fire had not affected “essential” equipment.

However the ongoing military operation around the site meant the situation was “very fragile,” IAEA Director General Rafael Mariano Grossi warned.

Speaking at a press conference in Vienna on Friday, the IAEA’s Rossi said the safety of the reactors had not been affected.

“We are fortunate there has not been a release of radioactive material and the integrity of the reactors has not been compromised,” he said. However, the operator and regulator have relayed to the IAEA that the situation on the ground is “extremely tense and challenging,” he warned.

He explained that a Russian projectile had hit a building within the site, causing a localized fire, but none of the reactors were affected and radiation monitoring systems are fully functional.

Ukrainian staff are still at the helm of operations at the plant, but “effective control” of the site was in the hands of Russian forces, Grossi said, adding: “I hope the distinction is clear.” He said that what happens next at Zaporizhzhia is “a situation that is very difficult to sustain, very fragile” while there is an active military operation and Russian forces in control. “This is unprecedented,” he said. “Completely uncharted waters.”

Grossi later told CNN’s Christiane Amanpour that although radioactive material was not released, it was a “close call.”

He told Amanpour that he had warned both sides that “the utmost restraint is to be exercised in and around this type of facility. Because wittingly or unwittingly, you can very quickly go into a disaster, and this is why we’re so concerned.”

The US ambassador to the UN, Linda Thomas-Greenfield, told the meeting that the world “narrowly averted a nuclear catastrophe last night.”

She called Russia’s reactions “reckless” and “dangerous,” saying it put Europe’s largest nuclear power plant at grave risk and threatened the safety of civilians in Russia, in the UK and across the European continent. Russian forces were also 20 miles away from Ukraine’s second largest nuclear facility, she noted.

“Nuclear facilities cannot become part of this conflict,” Thomas-Greenfield said. “Mr Putin must stop this madness, and he must stop it now.”

Zelensky pushes for no-fly zone

On Friday, Ukrainian President Volodymyr Zelensky accused Russian troops of committing a “terror attack” by intentionally firing at the power plant — potentially risking the lives of millions.

He later condemned NATO’s decision to rule out the implementation of a no-fly zone over the country.

NATO’s chief said Friday that a no-fly zone over Ukraine is not an option being considered by the alliance. “We’ve agreed that we should not have NATO planes operating over Ukrainian airspace or NATO troops on Ukrainian territory,” Secretary-General Jens Stoltenberg said at a press conference earlier in Brussels.

In a Facebook post, Zelensky questioned what the alliance’s members were thinking, saying, “All the people who will die from this day will also die because of you, because of your weakness, because of your disunity.” However, he also expressed his gratitude to NATO countries that have shown support for Ukraine.

Meanwhile, US Secretary of State Antony Blinken said the establishment of a no-fly zone in Ukraine by the US and it’s NATO allies could lead to a “full-fledged war in Europe,” but said Washington would continue to work with it’s allies to provide Ukrainians with the means to defend themselves from Russian aggression.

Nuclear plant under attack

Reports of the attack on the facility emerged early Friday morning, with video of the scene showing bursts of gunfire apparently directed at the Zaporizhzhia facility before dawn.

Flames could also be seen on video footage, though for some time it was unclear where the fire was or the scale of the threat posed to the facility.

Ukrainian authorities released video later on Friday from inside the facility’s control room, with an announcement ringing out on a PA system aimed at the Russian forces outside.

“Stop shooting at a nuclear dangerous facility. Stop shooting immediately! You threaten the security of the whole world!” the announcement says.

The Russian government has claimed Ukrainian “provocation” led to a firefight around the nuclear power plant.

In a video briefing, Russian Ministry of Defense spokesperson Maj. Gen. Igor Konashenkov said Russian forces took the city of Enerhodar, the Zaporizhzhia nuclear power plant and the territory adjacent to it on February 28. Konashenkov claimed the plant’s technical staff continued regular work on the facilities, but that Ukrainian forces attempted a “monstrous provocation” in the early hours of Friday. Konashenkov also claimed the Ukrainians had set fire to the training building themselves.

CNN could not immediately verify any details of the firefight on the territory of the plant.

The Russian government has routinely and without evidence claimed the Ukrainian government is staging “provocations” to provoke a military response by Western governments.

It’s the not first nuclear plant to come under threat from the Russian invasion. On the first day of the assault, Russian forces seized control of the Chernobyl power plant in northern Ukraine, the site of the world’s worst nuclear disaster, according to Ukrainian officials.

The Chernobyl nuclear power plant reactor exploded in 1986, when Ukraine was part of the Soviet Union — sparking a disaster that affected, directly or indirectly, nine million people, due to radioactive materials released into the atmosphere.

The IAEA said in a statement that Ukraine had informed it staff held at the Chernobyl nuclear power plant since Russian military forces took control of the site a week ago were facing “psychological pressure and moral exhaustion.”