The Zaporizhzhia power plant -- Europe's largest -- was seized by Russian soldiers in the opening days of the invasion and has remained on the front line ever since.

This week the facility has come under fire repeatedly, with Kyiv and Moscow trading blame for the dangerous escalation.

The mayor of the southeastern city of Energodar, where the plant is located, told AFP "the risks are increasing every day".

"What is happening there is outright nuclear terrorism," Dmytro Orlov told AFP by telephone from the city of Zaporizhzhia, which remains under Ukrainian control.

"It can end unpredictably at any moment."

Kyiv has accused Moscow of basing troops and weapons in the station, launching attacks and using the atomic plant as a shield from returning fire.

In his televised address Saturday, Ukrainian President Volodymyr Zelensky accused Russia of nuclear "blackmail" and using the plant to "intimidate people in an extremely cynical way".

"The situation is hazardous, and what causes the most concern is that there is no de-escalation process," said Orlov.