The Zaporozhye nuclear power plant (ZNPP) has been cut off from the power grid again, its Russian administrators and the Ukrainian atomic agency confirmed on Monday.

"As a result of the shutdown of the Dneprovskaya 750 kV high-voltage line, the Zaporizhzhia NPP lost external power supply," the Russian administration wrote on Telegram, adding the causes of the outage were being investigated and that backup diesel generators were keeping it working.

Vladimir Rogov, a senior official of the Zaporozhye regional administration, said the plant was "completely" disconnected from external power supply after Ukraine disconnected a power line it controls.

On the other hand, Ukraine's nuclear agency Energoatom accused Russia of carrying out an attack on Monday morning that caused the power cut, saying it was the seventh instance of the plant entering "blackout mode" since Russian forces took control of it in March 2022.

Energoatom said the generators had enough fuel reserves to last 10 days.

"If it is impossible to restore external power to the plant during this time, an accident with radiation consequences for the whole world may occur," it warned.

However, Yuriy Malashko, governor of the Zaporozhye Region region said there was a fire at one of the facilities in Zaporozhye city due to an overload in the power system.

"Problems with electricity supply that arose in the city of Zaporizhzhia are not related to shelling," Malashko said on Telegram.

The ZNPP, Europe's largest nuclear plant, used to supply around 20% of Ukraine's electricity and continued to function in the early months of the war, before halting power production in September.

None of its six Soviet-era reactors has since generated electricity, but the facility remains connected to the Ukrainian power grid for its own needs, notably to cool the reactors.

Read more: Grossi inspects ZNPP, sees no offensive weapons: Rosenergoatom