Russian Forces Are Retreating From Lyman: Ukraine Live Updates

Credit…David Guttenfelder for The New York Times

The head of the United Nations’ nuclear agency called on Saturday for the release of the director general of the Zaporizhzhia Nuclear Power Plant, who has been detained by Russia, saying that his detention has “a very significant impact” on the safety of the Russian-controlled facility.

The director general, Ihor Murashov, is responsible for nuclear and radiation safety, according to Energoatom, the Ukrainian national energy company. At around 4 p.m. Friday, a car carrying Mr. Murashov was stopped on the road leading to the plant, and he was blindfolded and taken to an unknown location, the company said.

The director of the International Atomic Energy Agency, Rafael M. Grossi, said in a statement on Saturday that Mr. Murashov’s detention “has an immediate and serious impact on decision-making in ensuring the safety and security of the plant.”

The sudden arrest also put a psychological strain on the rest of the plant’s staff, he added.

The nuclear plant, Europe’s largest, was seized by Russian forces in March but is run by Ukrainian engineers. Fighting nearby has raised international concern about an accident. Shelling has at times caused the plant to be disconnected from Ukraine’s power grid, which Ukraine’s energy minister has said put critical cooling systems at risk of relying solely on emergency backup power.

Ukraine’s Foreign Ministry called in a statement for Russia to immediately release Mr. Murashov and urged the U.N. nuclear agency to take “decisive measures.”

The I.A.E.A. has had two inspectors at the plant since September. It said in a statement on Friday that there had been a series of land mine explosions near the plant in recent days that was jeopardizing safety and security at the facility.

The latest blast, the sixth reported in a week, damaged a low-voltage cable outside the fence perimeter, according to the agency. The explosion was close to a nitrogen-oxygen facility and indirectly damaged a voltage transformer at one of the reactors, the statement said. Earlier in the week, the agency said that the land mines appeared to have been set off by animals.

Ukrainian and Russian military forces have accused each other of using the specter of nuclear disaster in brinkmanship in the war by making attacks near the plant. Mr. Grossi has repeatedly urged the establishment of a security zone in the area.

The plant is in the Zaporizhzhia region, part of the slice of eastern and southern Ukraine that President Vladimir V. Putin of Russia moved to illegally annex on Friday.

Ukrainian officials have noted the fatigue and stress of Ukrainian control room employees, saying that Russian soldiers had subjected them to harsh interrogations, including torture with electric shocks, suspecting them of sabotage or of informing the Ukrainian military about activities at the plant.