Tensions are running high in occupied Ukraine, with both Russia and Ukraine accusing each other of plotting to stage an attack on the Russian-controlled Zaporizhzhia nuclear power station.

The nuclear plant, which was seized by Russian troops, has long been the subject of mutual suspicions between the two warring sides, and any attack on the facility — Europe’s largest, with six reactors — could have catastrophic consequences.

A statement issued by the Ukrainian armed forces on Tuesday quoted “operational data” as saying that “explosive devices” had been placed on the roof of the station’s third and fourth reactors earlier that day, and an attack was possible “in the near future”.

“If detonated, they would not damage the reactors but would create an image of shelling from the Ukrainian side,” the statement on Telegram said.

It added the Ukrainian army stood “ready to act under any circumstances”.

Ukrainian President Volodymyr Zelenskyy used his nightly video message later that day to announce Russia was planning to “simulate an attack on the plant. Or they could have some other kind of scenario.”

“But in any case, the world sees — and cannot fail to see — that the only source of danger to the Zaporizhzhia nuclear power plant is Russia. And no one else,” Mr Zelenskyy said.

He said he had spoken to French President Emmanuel Macron about the issue, and the two leaders had “agreed [to] keep the situation under maximum control together with the IAEA”, the United Nations’ International Atomic Energy Agency.

Meanwhile, Renat Karchaa, an adviser to the head of Rosenergoatom, which operates Russia’s nuclear network, said Ukraine was planning to drop ammunition on the plant laced with nuclear waste transported from another of the country’s five nuclear stations.

Kremlin spokesman Dmitry Peskov on Wednesday said there was indeed “a great threat of sabotage by the Kyiv regime, which could be catastrophic in its consequences”, adding that “all measures are being taken to counter such a threat”.

Neither Mr Zelenskyy, the Ukrainian military, Mr Karchaa or Mr Peskov offered any evidence to the public in support of their allegations.

IAEA wants nuclear plant demilitarised

The IAEA, the UN’s nuclear watchdog, has been trying for more than a year to clinch a deal to ensure the plant is demilitarised and reduce the risks of any nuclear accident.

Each side regularly accuses the other of shelling the area around the plant and risking a major nuclear mishap.

IAEA director-general Rafael Grossi has visited the plant three times since the Russian takeover, but has so far failed to reach any agreement to keep the facility safe from shelling.

The Ukrainian side isn’t happy about the lack of progress, with Zelenskyy adviser Mykhailo Podolyak recently telling Ukrainian television that Mr Grossi had proved ineffective in trying to uphold safety at the plant.

“Any disaster at Zaporizhzhia could have been prevented if [Mr Grossi had been] clear straight away,” Mr Podolyak said, accusing the IAEA of flip-flopping in its approach to the problem.

“That is, instead of this clowning around that this man is doing. And when there is a disaster, he will say they had nothing to do with it and warned about the dangers.”

Kremlin dismisses Xi report as ‘fiction’

The Kremlin on Wednesday dismissed as “fiction” a report in The Financial Times that Chinese President Xi Jinping had personally warned Russian President Vladimir Putin against using nuclear weapons in Ukraine.

The British newspaper, citing unidentified Western and Chinese officials, reported that Mr Xi had issued the warning to Mr Putin at a face-to-face meeting in March.