Rafael Grossi urged Russia and Ukraine -- who blame each other for the attacks on the plant -- to immediately allow nuclear experts to assess the damage and evaluate safety and security at Europe's largest nuclear powerplant.
The head of the UN nuclear watchdog warned Thursday that "very alarming" military activity at Europe's largest nuclear plant in southeastern Ukraine could lead to dangerous consequences for the region.
Rafael Grossi urged Russia and Ukraine -- who blame each other for the attacks at the Russian-controlled Zaporizhzhia facility -- to immediately allow nuclear experts to assess the damage and evaluate safety and security at the sprawling nuclear complex, where the situation "has been deteriorating very rapidly".
"This is a serious hour, grave hour, and the IAEA must be allowed to conduct its mission in Zaporizhzhia as soon as possible," Grossi told the United Nations Security Council on Thursday.
He pointed to shelling and several explosions at Zaporizhzhia last Friday that forced the shutdown of the electrical power transformer and two backup transformers, forcing the shutdown of one nuclear reactor.
Last week, Grossi said that the situation at Zaporizhzhia was "completely out of control".
On Thursday, he demanded a halt to military actions "that have even the smallest potential to jeopardise nuclear safety" at such an important installation.
While a preliminary assessment by experts found "no immediate threat to nuclear safety" at the plant from the shelling and military actions, "this could change at any moment," he warned.
Grossi's appeal echoed UN Secretary-General Antonio Guterres' call earlier on Thursday for an end to all military activity around the Zaporizhzhia plant, warning that any damage could lead to "catastrophic consequences" in the vicinity, the region and beyond.
Grossi, director general of the International Atomic Energy Agency, gave a virtual briefing to the U.N. Security Council at a meeting called by Russia to discuss what Moscow claims were Ukrainian attacks on the plant.
While the plant is controlled by Russia, its Ukrainian staff continues to run the nuclear operations. It is in Enerhodar, a city seized by Russian troops in early March soon after they invaded Ukraine.
Grossi said statements received from Russia and Ukraine "are frequently contradicted," and the IAEA can't corroborate important facts unless its experts visit Zaporizhzhia.
The Ukrainian state company operating the plant, Enerhoatom, said there was renewed Russian shelling of the Zaporizhzhia facility and nearby buildings Thursday.
"Five (hits) were recorded near the plant management's office — right next to the welding site and the storage facility for radiation sources," Enerhoatom said in a post on its official Telegram channel. "The grass caught fire over a small area, but fortunately, no one was hurt."
At the end of the council meeting, Grossi said there was "a common denominator" among the 15 members: "Everybody agrees that nuclear safety and security must be preserved. … And everybody believes that this mission must take place."
"So, it's no longer a matter of if, it's only a matter of when," the UN nuclear chief said. "The when must be as soon as possible."