Europe's largest nuclear power plant at Zaporizhzhia in southern Ukraine was disconnected from the power grid, Ukrainian nuclear operator Energoatom said Thursday, warning that creates a safety risk.

"The actions of the invaders caused a complete disconnection of the ZNPP from the power grid — for the first time in the history of the plant," Energoatom said in a statement.

The power plant — which has six reactors, two of which are operating — was seized by Russian troops in March but its daily operation has remained under the control of Ukrainian staff.

The Ukrainian utility said that fires at ash dumps near the power plant twice cut off the last transmission line linking the facility to the Ukrainian grid. It added that three other transmission lines "were damaged during Russian shelling earlier."

However, the Russian-installed regional governor said: "At the moment, the power supply to all cities and districts of the Zaporizhzhia region has been restored" from the plant after earlier disruptions, CNN reported.

Rafael Mariano Grossi, director general of the International Atomic Energy Agency, told France 24 earlier Thursday: "If you have the external power feeding the plant and thus feeding the cooling system of the reactors interrupted, then you could be very, very soon in a place where you don’t want to be" and that could potentially "lead to a nuclear accident."

Grossi added that he is still negotiating the terms of an IAEA safety mission to Zaporizhzhia and hopes to go there "within days."