Russia and Ukraine 'interested' in nuclear safety zone: IAEA chief

"What we need is Ukraine and Russia to agree on a very simple principle of not attacking or shelling the plant," he told reporters in Vienna — dubbing the UN nuclear watchdog proposal as "realistic".

Under such an agreement, both parties would have to stop military action aimed at the plant or at a radius which could affect its normal operations — but details over that safety radius are still unclear.

Establishing a safety zone at Zaporizhzhia, however, would not trigger larger demilitarisation of the area.

"I have to work within my mandate and cannot go into areas that have to do with larger demilitarisation," Grossi said.

The IAEA chief also confirmed that the last operating reactor at Ukraine's nuclear power plant has now been shut down thanks to the restoration of an external power supply, but he stressed that Ukraine aims to keep the plant operational given its importance to keeping electricity running in the country.

A secure external power supply is key to ensuring nuclear safety, even in the case of a cold shutdown, the IAEA has repeatedly said.

In a report earlier this month, the UN agency noted that Zaporizhzhia on several occasions "lost, fully or partially, the off-site power supply as a result of military activities in the area".

"If external power is interrupted, you may still face a nuclear accident even if the reactors are not providing energy to the Ukrainian grid," Grossi warned, adding that it would be "logical" to conclude that Ukraine would resume operations at the nuclear plant after securing off-site power lines.

That decision, nevertheless, should be made by Ukraine, Grossi said. The nuclear power plant has been under Russian control since early March, but Ukrainian staff are still running the plant.

French president Emmanuel Macron urged Russian president Vladimir Putin to withdraw heavy and light weapons from Zaporizhzhya, during a telephone conversation on Sunday.

Macron also called on Moscow to follow the recommendations of the IAEA in order to ensure the safety of the plant.

Two inspectors from the IAEA remain at the Zaporizhzhia power plant, after the UN atomic agency held a safety mission earlier this month.

Ukraine's president Volodymyr Zelensky said on Sunday that Russian shelling caused electricity blackouts in the region of Kharkiv and Donetsk and partial power interruptions in the Zaporizhzhia, Dnipropetrovsk and Sumy regions.