The United Nation’s nuclear watchdog has said safety principles at a Russian-controlled power plant in Ukraine “have been violated” and urgent steps are needed to avoid a nuclear accident.

International Atomic Energy Agency director general Rafael Grossi said the safety situation at the Zaporizhzhia – Europe’s biggest nuclear power facility - was “completely out of control”.

“Every principle of nuclear safety has been violated. What is at stake is extremely serious and extremely grave and dangerous”, - Grossi said.

Russian forces have occupied the plant since seizing it in early March, but it is staffed by Ukrainians, and the nuclear watchdog said its communication with those staff was patchy.

Grossi pleaded with both Russia and Ukraine to quickly allow a team of inspectors into the plant so they could assess the situation.