Updated

Three men in their 20s have been arrested in possession of a drone near a French nuclear reactor, the first such arrests since a spate of mysterious drone overflights of reactors began in early October.

There have been at least 15 sightings of drones over nuclear reactors around France, raising security concerns in a country heavily dependent on atomic energy for electricity. The zone around nuclear plants is off limits.

The National Gendarmerie said the men were being questioned after being found with a drone Wednesday afternoon near the Belleville-sur-Loire reactor in the Cher region south of Paris.

It didn't immediately provide more details.

The drones — unmanned aircraft — that overflew nuclear plants ranged from very small to one spanning two meters (six feet).