Fire Breaks Out at Zaporizhzhia Nuclear Complex

A fire broke out early Friday morning at a complex in southern Ukraine that is home to Europe’s largest nuclear power plant, after Russian troops fired on the area, Ukraine’s foreign minister said.

Security camera footage filmed early on Friday and verified by The Times showed a building ablaze inside the power complex near a line of military vehicles. The videos appeared to show people in the vehicles firing at buildings in the power plant. It’s unclear if the vehicles were Russian or Ukrainian.

The condition of the plant, and how many of its reactors were producing energy, was unknown. The fire broke out after a Russian attack on a training building outside the perimeter of the plant, Reuters reported early Friday, citing a statement by Ukraine’s state emergency service.

The foreign minister, Dmytro Kuleba, said the Russian army was “firing from all sides” on the Zaporizhzhia complex, which includes the largest reactor site in Europe. He said on Twitter that a disaster could be “10 times larger than Chernobyl,” referring to the disaster at that nuclear site in 1986. “Russians must immediately cease fire and allow firefighters to establish a security zone,” he said.

Rafael Mariano Grossi, the director general for the International Atomic Energy Agency, said on Twitter that he had spoken with Ukrainian officials about the serious situation at the plant. He appealed for a halt to the fighting and warned of “severe danger” if the reactors were hit.

Mr. Grossi’s agency also released a statement saying it had been informed by Ukrainian regulators that there had been no reported change in radiation levels at the plant. The American Nuclear Society also condemned the Russian attack on the reactor complex but noted that, so far, “there are no indications that any damage.” The latest readings of its radiation levels are, the statement added, “within natural background levels.”

Earlier in the day, Mr. Grossi had said that “a large number of Russian tanks and infantry” had entered Enerhodar, a town next to the plant, and that infantry troops were “moving directly towards” the reactor site.

The mayor, Dmitry Orlov, told a local radio station that fierce fighting between Russian and Ukrainian soldiers had been raging on the approaches to the plant, according to the station’s Twitter account. The mayor called for an immediate cease-fire.

The Zaporizhzhia nuclear complex, on the Dnieper River roughly a hundred miles north of Crimea, is the largest not only in Ukraine, but also in Europe. According to the International Atomic Energy Agency, its six reactors produce a total of 6,000 megawatts of electric power.

In comparison, the Chernobyl plant in northern Ukraine produced 3,800 megawatts — about a third less. (A megawatt, one million watts, is enough power to light 10,000 hundred-watt bulbs.) The four reactors of the Chernobyl complex were shut down after one suffered a catastrophic fire and meltdown in 1986.

The reactors’ cores are full of highly radioactive fuel. But an additional danger at the Zaporizhzhia site is the many acres of open pools of water behind the complex where spent fuel rods have been cooled for years. Experts fear that errant shells or missiles that hit such sites could set off radiological disasters.

For days, social media reports have detailed how the residents of Enerhodar set up a giant barrier of tires, vehicles and metal barricades to try to block a Russian advance into the city and the reactor site. Christoph Koettl, a visual investigator for The New York Times, noted on Twitter that the barricades were so large that they could be seen from outer space by orbiting satellites.

Starting this past Sunday, three days into the invasion, Ukraine’s nuclear regulator began reporting an unusual rate of disconnection: Six of the nation’s 15 reactors were offline. On Tuesday, the Zaporizhzhia facility was the site with the most reactors offline.