Explosions Hit Russian Ammunition Depot in Crimea

Russian officials blamed “sabotage” for the explosions, without indicating potential suspects. Ukraine didn’t claim responsibility but officials in Kyiv hinted at Ukrainian involvement.

“Demilitarization in action,” presidential adviser

Mykhailo Podolyak

wrote on Twitter.

“The demilitarization operation of the Armed Forces of Ukraine will continue in a precise fashion until the full deoccupation of Ukrainian territories,”

Andriy Yermak,

head of Ukraine’s presidential administration, wrote on Telegram. “Crimea is Ukraine.”

The explosions underscore Russia’s vulnerabilities as Ukraine seeks to retake territory in its south that Russia occupied in the early stages of the war. Ukraine, which lacks the forces for a head-on assault, has sought to erode Russia’s ability to wage war by targeting ammunition dumps, command posts and bridges, usually with long-range rocket launchers provided by the U.S. Russia has reinforced its military in the south with thousands of troops that were transferred from eastern Ukraine.

Blasts at a Russian air base in Crimea last week destroyed several warplanes, according to satellite images and Ukrainian and Western officials. Kyiv mocked Russia over the incident but didn’t take responsibility. Russia blamed an ammunition explosion and said no warplanes were lost.

The damage to Russian facilities in Crimea has provided a morale boost for Ukrainian forces, which surrendered the peninsula in 2014 with little resistance and have been losing ground in the country’s east. The incidents also demonstrate a new threat to Russian supply lines from territory that Moscow considers its own in a war that it has sought to portray as a limited operation.

Videos shared on social media by Ukrainian officials purporting to show the scene of the blasts Tuesday showed a large fire and plumes of smoke with the sound of explosions crackling.

Russian officials said the exploding ammunition caused damage to a railway line that leads from eastern Crimea, where a bridge connects the peninsula with the Russian mainland. The Russian Ministry of Defense said power lines and infrastructure, as well as civilian homes, were also damaged.

Authorities halted passenger trains at a station to the southeast of the fire and transferred passengers to buses. Officials said trains would resume Tuesday after repairs to the tracks were completed.

Russia relies heavily on rail to transport military vehicles, equipment and troops.

Speaking via video to the Moscow international security conference on Tuesday, President

Vladimir Putin

repeated his claim that the U.S. is to blame for the war, which the Kremlin leader launched on Feb. 24 in an attempt to take control of Ukraine.

Russian Defense Minister

Sergei Shoigu

said the Himars rocket systems that Ukraine has used to target Russian military infrastructure and supply lines have had no effect on Russia’s military campaign. Western and Ukrainian officials and analysts have said the systems have dented Russia’s ability to wage war by forcing its military to locate ammunition supplies and command posts further from the front lines.

Fighting around the Zaporizhzhia nuclear-power plant has intensified in recent days. Ukrainian President

Volodymyr Zelensky

on Monday accused Russia of rejecting the security demands of the European Union and other countries that have called on Russia to withdraw its forces from the plant.

The spokesman for United Nations Secretary-General

António Guterres

said U.N. officials haven’t canceled or blocked a visit by the International Atomic Energy Agency to the plant, rejecting claims from Russian officials.

“The U.N. Secretariat has assessed that it has in Ukraine the logistics and security capacity to be able to support any IAEA mission to the Zaporizhzhia Nuclear Power Plant from Kyiv, should both Russia and Ukraine agree,”

Stéphane Dujarric

said.

Write to James Marson at james.marson@wsj.com