The Ukrainian nuclear operator Energoatom on Wednesday accused Russia of again striking the Zaporizhzhia atomic power plant in southern Ukraine.
"Russian terrorists bombed the Zaporizhzhia nuclear power plant again during the night," Energoatom said on Telegram.
The strike damaged a power line causing the stoppage of several transformers of the number six reactor of the plant and forcing a brief start of emergency generators, Energoatom said.
"Even the presence of inspectors from the International Atomic Energy Agency (IAEA) does not stop" the Russians, it said, calling on the agency to "more resolute actions" against Moscow.
Europe's largest atomic facility, located in Russian-held territory in Ukraine, has become a hot spot for concerns after tit-for-tat claims of attacks there.
The plant was seized by Russian troops in March and shelling around the facility has spurred calls from Kyiv and its Western allies to de-militarise areas around nuclear facilities in Ukraine.
Early in the war there was fighting around Chernobyl in the north, where an explosion in 1986 left swathes of the surrounding territory contaminated.
French President Emmanuel Macron this month urged his Russian counterpart Vladimir Putin to withdraw heavy weapons from the Zaporizhzhia region, while the Russian leader cautioned against the potential "catastrophic" consequences of fighting there.
A monitoring team of the IAEA deployed there in early September.
Russia was accused Monday of bombing a third nuclear plant site, the Pivdennoukrainsk plant in the southern Mykolaiv region.
Moscow is stepping up "nuclear blackmail", said the plant's director after the strike caused a large crater seen by AFP journalists hundreds of metres from the plant.