The Russian-occupied Zaporizhzhia nuclear energy plant in southern Ukraine was operating on emergency diesel generators on Monday after Russian shelling cut off its external power supply, Ukraine's state nuclear energy company said.
Energoatom said the backup generators had kicked in after the only substation supplying the plant (ZNPP) with electricity from the Ukrainian grid was damaged before dawn.
Although the plant's six reactors have been shut down for weeks, they need a constant supply of electricity to keep the nuclear fuel inside cool and prevent a meltdown.
Energoatom said Russia was now targeting all the substations supplying Ukrainian nuclear power stations with electricity, an accusation that Russian state nuclear energy company Rosatom did not immediately comment on.
"In recent days, the Russian invaders, shelling the entire territory of Ukraine, deliberately targeted substations connected by high-voltage communication lines to Ukrainian nuclear power plants," Energoatom said on its website.
Writing on Facebook, Ukrainian Energy Minister German Galushchenko said: "Such nuclear blackmail by a terrorist country should not go unanswered by the world community! Ukraine needs protection of the skies above its energy facilities!"
Zaporizhzhia is one of four Ukrainian regions Russia has proclaimed as annexed but only partly occupies.
Russian forces have occupied the ZNPP, Europe's largest nuclear power station, since shortly after Moscow's invasion of Ukraine nearly eight months ago. It is still operated by its Ukrainian staff.
Russia and Ukraine have blamed each other repeatedly for shelling at the site of the plant that has damaged buildings and threatened a catastrophic nuclear accident.
The International Atomic Energy Agency (IAEA) is pushing for a protection zone to be set up to prevent further shelling, and the head of the U.N. nuclear watchdog visited both Moscow and Kyiv last week.
(Reporting by Kyiv newsroom, Editing by Timothy Heritage and Bernadette Baum)
