Moscow and Kyiv accused each other of starting a fire on the grounds of Europe's largest and now Russian-occupied Zaporizhzhia nuclear power plant in Ukraine on Sunday, with both sides reporting no sign of elevated radiation.

The U.N.'s International Atomic Energy Agency (IAEA) nuclear watchdog, which has a presence at the vast six-reactor facility, said that a fire at the Zaporizhzhia atomic power plant in southern Ukraine did not appear to represent a threat to nuclear safety.

Russian state news agencies, TASS and RIA, cited the country's nuclear energy company Rosatom as saying the main fire was extinguished shortly before midnight on Sunday.

The fire comes less than a week after Ukraine's forces launched their largest incursion into Russian territory since the war-start in 2022, a surprise move that has brought conflict into a new phase, after weeks of Moscow's battlefield gains.