Ukraine invasion: One reactor at Zaporizhzhia nuclear plant shut down after Russian shelling

One of two operational reactors at Ukraine's Russian-held Zaporizhzhia nuclear plant complex has been shut down due to Russian shelling, operator Energoatom said on Thursday.

"As a result of another mortar shelling by Russian ... forces at the site of the Zaporizhzhia nuclear power plant, the emergency protection was activated and the operational fifth power unit was shut down," Energoatom wrote on the Telegram messaging app.

Energoatom added that "power unit No. 6 continues to work in the energy system of Ukraine" and is supplying electricity for the power plant's own needs.

Due to shelling, a power supply line used for the plant's own needs was also damaged and auxiliary generators had to be activated.

Diesel generators were being used at non-operating power unit No. 2, the company said.

On Thursday, a mission of UN nuclear experts set out to the plant, even as both sides in the conflict reported fighting in the area.

Conditions at the plant, Europe's largest, have been unraveling for weeks, with Moscow and Kyiv trading blame for shelling in the vicinity and fuelling fears of a radiation disaster.

Earlier in the day, Rafael Grossi, chief of the International Atomic Energy Agency (IAEA), said the mission was aware of "increased military activity in the area" but was pressing ahead with its plan to visit the facility and meet staff.