The nuclear plant has been at the centre of fighting since it was captured by Russian forces in 2022, and both sides have accused each other of compromising its safety.

The surroundings of the plant have been repeatedly targeted by shelling, which resulted in the plant being severed from the grid several times, raising fears of a major nuclear accident.

International Atomic Energy Agency (IAEA) experts "for the past two weeks... have not been allowed to access the reactor halls of units 1, 2 and 6," IAEA Director General Rafael Grossi said in a statement.

"This is the first time that IAEA experts have not been granted access to a reactor hall of a unit that was in cold shutdown," the statement added.

Furthermore, access to some parts of the plant's turbine halls continues to be restricted, and the IAEA is still awaiting access to the reactor rooftops planned on 19 December that "didn't happen due to stated security concerns".

Grossi said his team will continue to request access to the reactor halls, where the reactor core and spent fuel are located.

Since September 2022, IAEA officials have been on the ground monitoring safety at the plant, which requires constant maintenance to prevent overheating.

It stopped supplying electricity to Ukraine's grid in September 2022, and has been repeatedly rocked by shelling and drone attacks throughout the conflict.