VIENNA - The head of the Russian-occupied Zaporizhzhia nuclear power plant (ZNPP) in Ukraine who was detained over the weekend in what Ukraine called a Russian act of terror will not return to that job, the UN nuclear watchdog said on Tuesday.

Ukraine said a Russian patrol detained Ihor Murashov on Friday as he travelled from Europe's largest nuclear power plant to the town of Enerhodar, where many of the plant's staff live.

Ukrainian staff continue to operate the plant in conditions the International Atomic Energy Agency says put safety at risk.

IAEA chief Rafael Grossi said on Monday that Murashov had been released, without specifying whether or when he would return to the plant.

"The IAEA understands that Mr (Ihor) Murashov is now with his family in territory controlled by Ukraine and will not be continuing with his duties at the ZNPP," the IAEA said in a statement on Tuesday.

"It is not yet clear who will replace him in this role."

Late on Saturday, the IAEA said his detention placed additional stress on the plant's already strained staff.

"His absence from duty in this way also has an immediate and serious impact on decision-making in ensuring the safety and security of the plant," the agency said at the time.

There are various threats to the plant's safety, including shelling that Russia and Ukraine have blamed on each other.

Grossi is due to travel to Kyiv and Moscow later this week in a bid to set up a protection zone around the plant to reduce the risk of a catastrophic accident. REUTERS