The head of the International Atomic Energy Agency (IAEA) on Thursday called for "maximum restraint" after Sunday's drone attacks on the Zaporizhzhia nuclear power plant (ZNPP), which he said have significantly increased the risk of a nuclear accident.

"Direct attacks against the ZNPP marked a major escalation of the nuclear safety and security dangers in Ukraine," IAEA Director-General Rafael Grossi told a special meeting of the agency's 35-nation Board of Governors.

The meeting was convened at the request of Russia and Ukraine to discuss the attacks on ZNPP, which hit the reactor dome of Unit 6 of the plant, and caused at least one casualty.