The head of the U.N. nuclear watchdog agency warned Monday that the danger of a major nuclear accident at Ukraine’s Zaporizhzhia Nuclear Power Plant remains “very real.”

“We are getting dangerously close to a nuclear accident,” Rafael Mariano Grossi, director general of the International Atomic Energy Agency (IAEA), told the U.N. Security Council.

The nuclear plant, Europe’s largest, came under several attacks in the early part of Russia’s invasion of Ukraine. Russian forces have occupied the facility since March 2022. The IAEA worked out an agreement to station one of its teams there to monitor the facility and any damage to its systems.

Grossi said that over the past 10 days, the plant has sustained several direct attacks — the first since November 2022. He did not say who carried them out.

In one direct hit, the containment dome of a reactor building was struck. Grossi said the damage to the structure was not significant, but the attack set a dangerous precedent.

Two other attacks were near the main reactor buildings and resulted in at least one casualty.

“These reckless attacks must cease immediately,” Grossi said.

He warned that two years of war are weighing heavily on nuclear safety at the plant.

“We cannot sit by and watch as the final weight tips the finely balanced scale,” he said.

Russia and Ukraine each blame the other for the strikes.

“Ukraine’s shelling of ZNPP cannot be justifiable on any grounds, including military goals,” Russian Ambassador Vassily Nebenzia said, referring to the plant by its initialism.

He claimed that Russia has never stationed heavy weaponry at the plant nor attacked from its territory.

Grossi confirmed to reporters that “there is no heavy weaponry there” but added that “the vicinity is something else.”

Ukraine’s ambassador said the recent attacks were “a well-planned false flag operation” by Russia.

“The only way out of the current, very precarious situation is complete demilitarization and deoccupation of the ZNPP and adjacent territories,” Ukrainian Ambassador Sergiy Kyslytsya said.