Ukrainian and Russian officials have repeatedly blamed each other for attacks on the plant, in the Zaporizhzhia regional city of Enerhodar, since it was captured by Russian forces shortly after their February 2022 invasion.
“This cannot happen,” Mr Grossi said. “No one can conceivably benefit or get any military or political advantages from attacks against nuclear facilities. This is a no go.
“I firmly appeal to military decision makers to abstain from any action violating the basic principles that protect nuclear facilities.”
The head of the UN’s International Atomic Energy Agency added it was the first such attack since November 2022, when he set out five principles to avoid a serious nuclear accident.
Mr Grossi did not publicly blame Ukraine or Russia for the attack, which he described as “reckless” and a “major escalation”.
Officials at the Russian-controlled plant said the site was attacked on Sunday by Ukrainian military drones, including a strike on the dome of its sixth power unit.
Plant authorities said there was neither critical damage nor casualties and that radiation levels at the facility were normal after the strike.
But later on Sunday, Rosatom, the Russian state-owned nuclear agency, said that three people had been wounded in an “unprecedented series of drone attacks”.
The International Atomic Energy Agency (IAEA) said on Sunday that its experts had been informed of the drone strike and that “such detonation is consistent with IAEA observations”.
In a separate statement, the IAEA confirmed the physical impact of drone attacks at the plant, including at one of its six reactors. One casualty was reported, it said.
“Damage at unit 6 has not compromised nuclear safety, but this is a serious incident with potential to undermine integrity of the reactor’s containment system,” it added.
Russia has used the plant to shield military vehicles, ammunition and other hazardous materials, which were parked inside a turbine hall, according to previously published evidence.
