PARIS (AP) — French officials are investigating an illegal drone overflight of the Atlantic coast base for France's nuclear-armed submarines, authorities said Friday.

French media reported that several drones were detected Thursday night over the Île Longue base in Brittany, western France, but military authorities wouldn't detail their number or type. The base is the home port of France's four nuclear ballistic missile submarines — Le Triomphant, Le Téméraire, Le Vigilant and Le Terrible.

Defense Minister Catherine Vautrin confirmed that troops at the base intercepted an overflight, without detailing whether they fired shots, used electronic jamming or other means against the aerial intruders. It wasn't clear who was responsible.

“Any overflight of a military site is prohibited in our country," Vautrin said. “I want to commend the interception carried out by our military personnel at the Île Longue base.”

A number of European Union member countries have reported mysterious drone flights in their airspace in recent months. Some led to airport shutdowns, disrupting commercial flights. Others have been detected near or over military facilities.

Russia has been blamed for a number of airspace violations, notably in Estonia and Poland.