Ukraine's state nuclear company has accused the head of the UN's nuclear watchdog of lying over a planned visit to a Russian-controlled power station.

Rafael Grossi said on Monday that Ukraine had invited the International Atomic Energy Agency (IAEA) to visit the Zaporizhzhia nuclear plant.

But Energoatom said there was no invitation, and that any visit would legitimise Russia's presence there.

Mr Grossi called the allegation of lying "absurd".

"It's a war and there are emotions and people have very strong positions," he said in an interview with the BBC.

But he claimed his organisation had a contractual obligation to perform safety inspections, arguing that this is not a "courtesy invitation that can or cannot be extended".

He tweeted on Monday that he was working to send an expert mission to the plant, writing "Ukraine requested us, we will go there".

The IAEA is a UN-based organisation which works with states to promote the safe use of nuclear technology.

Ukraine's state nuclear company Energoatom released a furious statement on Tuesday, accusing Mr Grossi of lying by claiming that Ukraine had requested the visit. It said any visit would be a "means to legitimise the stay of the occupiers".

According to Russian media, the IAEA is in touch with Russian authorities over a possible visit.

Russia seized the Zaporizhzhia nuclear power plant - the largest in Europe - in early March, just days after it invaded Ukraine. There was an international outcry after buildings at the power station were shelled by Russian forces as they seized it.

No critical infrastructure was damaged and radiation levels remained normal.

The plant continues to operate, with Ukrainian staff working under Russian orders.

Mr Grossi has for months said that the situation at Zaporizhzhia poses a safety risk and that he wants to lead a mission there.

Safety data from Zaporizhzhia is no longer being transmitted to the IAEA, and Ukrainian staff are working under "extremely stressful and challenging working conditions", the IAEA head said in a statement on Monday.

Energoatom claimed in its statement that the transmission of safety data from the plant was cut off with the IAEA's consent. Mr Grossi dismissed that allegation as "careless statements" made under "high emotion".

On Tuesday, the IAEA said radiation detectors at the decommissioned Chernobyl nuclear power plant, which was also under Russian control for several weeks, were back online for the first time after Ukraine took back control of the plant.

Radiation levels there were reported to be in line with those measured before the conflict.