Russia on Sunday said that a Ukraine drone attack hit the Moscow-controlled Zaporizhzhia Nuclear Power Plant, as the International Atomic Energy Agency (IAEA) urged restraint.

The Zaporizhzhia atomic plant, Europe's largest, has been occupied by Russian forces since the start of their 2022 Ukraine offensive.

"The Ukrainian Armed Forces attacked the dome of the sixth power unit of the Zaporizhzhia Nuclear Power Plant (ZNPP)," the Moscow-controlled management of the plant said on social media.

It said there was no radioactive release as a result of the attack.

Later on Sunday, the IAEA said on X, formerly Twitter, that its experts had "confirmed physical impact of drone attacks at ZNPP today, including at one of its six reactors".

IAEA head Rafael Grossi specified that "at least three direct hits against ZNPP main reactor containment structures took place".

"This cannot happen. I firmly appeal to military decision makers to abstain from any action violating the basic principles that protect nuclear facilities," Grossi stressed.

According to the IAEA, the damage at unit six had not compromised nuclear safety, but it warned that "this is a serious incident with potential to undermine (the) integrity of the reactor's containment system".

Russia's nuclear agency ROSATOM urged the West and Grossi to "categorically condemn the attempt to escalate the situation around the biggest nuclear power plant in Europe".

It said the drone hit the plant's canteen, wounding three staff members, one of them "severely".

The IAEA said on late Sunday that one casualty was reported.