Security Chiefs Probe Reason for Unmanned Drones Over French Nuclear Sites

French security chiefs are investigating a spate of mysterious and illegal flights by tiny, unmanned drones over French nuclear power stations.

A government official told The Associated Press that authorities have counted about 15 drone flights over a half-dozen nuclear sites since October 1. Authorities insist that France’s nuclear facilities are designed to handle seismic and security risks, including those possibly posed by drones.

“Drone overflights are currently being carried out in a repeated and simultaneous manner over certain nuclear sites in our country,” the prime minister’s general secretariat for defense and national security, known as SGDSN, said in a statement sent Monday to the AP.

“The objective apparently sought by this type of organized provocation is to disrupt the chain of surveillance and protection at these sites,” it said.

Environment Minister Segolene Royal told French media Sunday that investigators have no leads about who was behind the flights. The SGDSN said authorities open legal cases for every suspected violation and those convicted could face fines of up to 75,000 euros ($94,000) and a year in prison.

Officials are increasingly keeping quiet about the government’s response. Interior Minister Bernard Cazeneuve said told French radio last week that authorities had ways to “neutralize” drones, but did not elaborate. On Monday, he told RTL radio that “the best way to be effective in this area is not to say what we’re doing.”

In recent years, Greenpeace France has led sporadic, peaceful incursions into French nuclear facilities to expose security vulnerabilities, but the environmental group has denied any connection to the drone flights.

France gets more than two-thirds of electricity from nuclear power, the highest proportion in the world.