"More than 150 people from the staff of the plant were captured" since the start of the Russian invasion in late February, Petro Kotin told AFP, adding that "some of them were later released, but there are those whose fate is still unknown".

"About 50 people are still in captivity," he said. ""They are plant employees."

"They periodically kidnap plant employees," Kotin said in an interview, reminding that the director general of the plant, Igor Murashov, had been held in captivity for several days before being released earlier this month.

"He had been kept in the basement for three days. Isn't it a torture if he sat on a chair for a day with a bag over his head?" Kotin said about Murashov, praising the role of Rafael Grossi, the head of the International Atomic Energy Agency (IAEA), in his release.

On Tuesday Energoatom accused Russia of detaining another two senior employees of Zaporizhzhia plant, the head of information technology Oleg Kostyukov and the plant's assistant general director Oleg Osheka.

The company said on social media that they were "kidnapped" and taken "to an unknown destination".

Last week Energoatom said Russia detained and mistreated the plant's deputy director general for human resources, Valeriy Martyniuk.

In a statement released late Tuesday the IAEA, which has experts at the nuclear site, announced that Martyniuk had been released.

Kotin told AFP on Wednesday that Martyniuk "had been held for four or five days and forced to sign a statement that he agrees with their (Russian) policy" at the plant.

Kotin reiterated that out of 150 people who were captured there were those who were "killed" and those "who were subjected to torture".

Kotin said the company was going to publish "in the coming days" the list of all those who had been detained.

Russian troops captured the Zaporizhzhia nuclear power plant -- Europe's largest atomic facility -- at the beginning of March, in the early days of Russia's invasion of Ukraine.

Moscow and Kyiv have traded blame for months over shelling near the Russian-held facility, sparking fears of a nuclear disaster and spurring calls to de-militarise areas around atomic facilities in Ukraine.

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