A Ukrainian drone crashed into a nuclear waste storage facility at the Kursk power plant in western Russia, damaging its walls, Russia's foreign ministry says, calling on other governments to condemn "an act of nuclear terrorism".
A ministry statement said Ukraine must have known that its actions could have caused a full-scale nuclear catastrophe that would have affected many countries.
"We call on all governments to issue a strong condemnation of Kyiv's barbaric actions, which are extremely dangerous and could lead to irreparable consequences," said foreign ministry spokeswoman Maria Zakharova.
Russia and Ukraine, which both operate nuclear power plants, have regularly accused each other of risking a nuclear calamity with irresponsible attacks, and the UN's nuclear watchdog - the International Atomic Energy Agency (IAEA) - has been monitoring the situation in Ukraine particularly closely.
Moscow said on Friday that it had thwarted Thursday's drone attack and two news outlets said an explosion had damaged the facade of a warehouse storing nuclear waste. Saturday's statement was the first official confirmation of the damage.
Zakharova said one explosive-packed drone had damaged the nuclear waste facility's walls while another two had hit an administrative building complex.
"According to preliminary data, the drones used in the attack on the nuclear power plant used components supplied by Western countries," she said, adding that such an attack must have had the permission of Ukraine's allies or possibly been ordered by them.
The Kursk plant, located in a region which borders Ukraine, said after the attack that there were no casualties and that radiation levels and operations were normal.
Ukrainian officials did not immediately respond to a request for comment on Saturday. Kyiv generally declines to confirm or deny military operations on Russian territory.
Russia in July complained that a Ukrainian drone had struck an apartment building in Kurchatov, a town built on the banks of a cooling pond for the Kursk nuclear power station.
Russia's FSB security service said in August last year that security around nuclear facilities had been beefed up after Ukrainian saboteurs had destroyed electricity lines supplying the Kursk plant, temporarily disrupting its functioning.
Kursk is one of several Russian regions that have regularly come under drone attack in the course of the 20-month war. The governor of Kursk reported a previous drone attack on Kurchatov on September 1.
Thursday night's incident came a day after Ukrainian President Volodymyr Zelenskiy said a Russian drone attack in Ukraine's western Khmelnitskyi region had probably targeted the area's nuclear power station.
The IAEA said that attack had destroyed "numerous windows" at the site but had not affected the Ukrainian plant's operations or its connection to the electricity grid.
Reuters was unable to independently confirm either incident.
