Russia said Ukraine struck the Zaporizhzhia nuclear power station controlled by Russian forces three times on Sunday and demanded the West respond, though Kyiv said it had nothing to do with the attacks.
The International Atomic Energy Agency, which has experts at the site, said it was the first time the nuclear plant, Europe's largest, was directly targeted since November 2022 and said the attack had endangered nuclear safety.
Russian forces took control of the plant in 2022 shortly after their full-scale invasion of Ukraine. Both Moscow and Kyiv have repeatedly accused each other of risking a nuclear accident by attacking the plant.
Russia's state nuclear corporation, Rosatom, said Ukraine attacked the plant three times on Sunday with drones, first injuring three near a canteen, then attacking a cargo area and then the dome above reactor No. 6.
"Zaporizhzhia nuclear power station has been subjected to an unprecedented series of drone attacks, a direct threat to the safety of the plant," Rosatom said.
"The radiation levels at the plant and the surrounding area have not changed," it said.
A Ukrainian intelligence official said Kyiv had nothing to do with any strikes on the station and suggested they were the work of Russians themselves.
"Russian strikes, including imitation ones, on the territory of the Ukrainian nuclear power plant ... have long been a well known criminal practice of the invaders," a spokesperson for Ukraine's HUR Main Intelligence Directorate, Andriy Usov.
Reuters was unable to immediately verify battlefield accounts from either side.
The nuclear plant has six Soviet-designed VVER-1000 V-320 water-cooled and water-moderated reactors containing Uranium 235 and also has spent nuclear fuel at the facility.
Reactors No. 1, 2, 5 and 6 are in cold shutdown while Reactor No. 3 is shut down for repair and Reactor No. 4 is in so-called "hot shutdown", according to the plant.
Russian Foreign Ministry spokeswoman Maria Zakharova urged world leaders to condemn the act of "nuclear terrorism."
Zakharova asked how many more times Ukraine would endanger nuclear safety at the plant before Western leaders took action.
The IAEA said its experts had confirmed three drone attacks and that Russian troops engaged what appeared to be a drone approaching reactor No. 6.
"This is a major escalation of the nuclear safety and security dangers facing the Zaporizhzhia Nuclear Power Plant. Such reckless attacks significantly increase the risk of a major nuclear accident and must cease immediately," IAEA Director General Rafael Grossi said in a statement.
"Attacking a nuclear power plant is an absolute no go," Grossi said.
"Although the damage at unit 6 has not compromised nuclear safety, this was a serious incident that had the potential to undermine the integrity of the reactor’s containment system," he added.