KYIV, Ukraine >> Europe’s largest nuclear plant was knocked off Ukraine’s electricity grid today, its last transmission line disconnected because of a fire caused by shelling, the facility’s operator and the U.N. atomic watchdog said.

The International Atomic Energy Agency said it was informed today by Ukrainian authorities that the reserve line “was deliberately disconnected in order to extinguish a fire.”

“The line itself is not damaged, and it will be reconnected once the fire is extinguished,” the IAEA said.

In the meantime, the plant’s only remaining operational reactor would “generate the power the plant needs for its safety and other functions,” the agency said.

Mycle Schneider, an independent analyst in Canada on nuclear energy, said that would mean the plant was likely functioning in “island mode,” producing electricity just for its own operations.

“Island mode is a very shaky, unstable, and unreliable way to provide continuous power supply to a nuclear plant,” Schneider said.

The incident fueled fears of a potential nuclear disaster at Zaporizhzhia, one of the 10 biggest nuclear plants in the world. Experts say its reactors are designed to protect against natural disasters and incidents such as aircraft crashes, but leaders around the world have appealed for it to be spared in the fighting because of the risk of a catastrophe.

Russia and Ukraine accuse each other of attacking the plant, which the Kremlin’s forces have held since early March. The plant’s Ukrainian staff continue to operate it.

The plant’s operator, Energoatom, said today that Russian forces have kept up “intensive shelling” around Zaporizhzhia in recent days despite the warnings. The Russian military accused Ukrainian forces of staging “provocations” there, including sending a drone, which was intercepted, and shelling the adjacent city of Enerhodar.

Ukrainian Energy Minister Herman Halushchenko said on Facebook that fighting around the power station made it impossible to repair damaged power lines, putting the world “once again on the brink of a nuclear disaster.”

The developments at Zaporizhzhia came on the eve of a report to the U.N. Security Council on Tuesday by the IAEA inspectors about what they found on their visit. The IAEA still has two experts at the plant after a perilous inspection that required its inspectors to travel through the fighting last week.

Ukraine’s presidential adviser, Mykhailo Podolyak, applauded the IAEA’s decision to leave some experts at the plant.

“There are Russian troops now who don’t understand what’s happening, don’t assess the risks correctly,” Podolyak said. “There is a number of our workers there, who need some kind of protection, people from the international community standing by their side and telling (Russian troops): ‘Don’t touch these people, let them work.’”

Meanwhile, in some of Moscow’s bluntest comments yet on the standoff between it and Western Europe over energy supplies, Kremlin spokesman Dmitry Peskov blamed Western sanctions for stoppages in Russia’s supply of natural gas to Europe.

“Other reasons that would cause problems with the pumping don’t exist,” Peskov said.

The sanctions on Moscow and Russian oil companies have created problems with equipment maintenance, he said, a claim that has been refuted by Western governments and engineers.

German officials have said Russian complaints about technical problems are merely a political power play. Germany’s Siemens Energy, which manufactured turbines the Nord Stream 1 pipeline uses, said turbine leaks can be fixed while gas continues to flow through the pipeline.

Russian energy company Gazprom announced Friday that a suspension of gas supplies heading westwards through the Nord Stream 1 pipeline would be extended indefinitely because oil leaks in turbines need fixing. That move brought a surge in European natural gas prices and walloped global stock markets.

High energy prices and possible shortages this winter in Western Europe have set alarm bells ringing among governments, notably those in the European Union. French President Emmanuel Macron today called for a 10% cut in his country’s energy use in coming weeks and months to avoid the risk of rationing and cuts this winter.

Elsewhere in Ukraine, the fighting raged on. The president’s office said at least four civilians were killed and seven others were wounded by new Russian shelling across several regions of Ukraine.

Ukrainian President Volodymyr Zelenskyy said there had been Russian shelling across much of southern and eastern Ukraine, including at Zelenodolsk, Nikopol, Chernihiv, and the Sumy and Kharkiv regions.

Russian rockets destroyed an oil depot in the Krivoy Rog region, sending up huge plumes of smoke, Ukrainian news reports said.

Amid increased Ukrainian strikes on the occupied Kherson region, Russian-installed authorities there said early today that for security reasons they were putting on hold their plans for a local referendum on whether the region should formally become part of Russia.

But by the afternoon, officials had a change of heart and said the ballot would go ahead as planned, though no date has been set.

In the eastern city of Sloviansk, workers with the Ukrainian Red Cross Society swept up debris today from a second rocket attack on its premises in a week. Nobody was hurt in either attack, said Taras Logginov, head of the agency’s rapid response unit. He blamed Russian forces and called the attacks war crimes.

In a row of apartment buildings across the road, the few residents who haven’t evacuated sawed sheets of plywood to board up their shattered windows.

Henadii Sydorenko sat on the porch of his apartment building for a break. He said he’s not sure whether to stay or leave, torn between his responsibility of taking care of three apartments whose owners have already evacuated and the increasing fear of the now frequent shelling.

“It’s frightening,” the 57-year-old said of the shelling. “I’m losing my mind, little by little.”