Emergency crews have raced to the scene of an explosion at a nuclear power plant in north-western France.
There is no nuclear risk, according to authorities, from the blast at Flamanville but at least five people have been treated for smoke inhalation.
The blast happened at 10am local time on Thursday morning.
Local official Jacques Witkowski told Reuters that the blast came from a mechanical part of the ventilator in the machine room, adding it was not being treated as a deliberate act of sabotage.
The Flamanville nuclear power plant is located on the Cotentin Peninsula in La Manche.
Senior official Olivier Marmion said the explosion happened outside the nuclear zone of the plant.
“It is a significant technical event but it is not a nuclear accident,” Mr Marmion told UK media.
The plant has been at the centre of recent protests over plans to turn on a third reactor, costing an estimated $14.7 million.
Two pressurised water reactors at the site have been operational since the 1980s.
The affected reactor has been taken off the grid.
News break - February 10