French naval forces opened fire on a swarm of unidentified drones that flew over one of the country’s most sensitive military installations, the Île Longue submarine base in western Brittany, officials confirmed on Friday.

Authorities say five drones were detected on Thursday night above the restricted military zone, home to France’s fleet of ballistic-missile nuclear submarines, the core of the nation’s nuclear deterrent. The regional gendarmerie said the aircraft were identified “by technical means” before marine infantry troops triggered counter-drone protocols and opened fire.

A military-judicial investigation has been launched, though officials have not confirmed whether any of the drones were brought down. Local authorities stressed that neither security nor base operations were compromised.

The incident marks the second reported drone presence near the site in recent weeks, though previous sightings did not breach the airspace directly above the base. Drone activity around Île Longue has been documented for more than a decade, but Thursday’s overflight is viewed as one of the most serious incursions to date.

Part of a Wider Pattern Across Europe

The episode adds to a growing number of drone incursions near NATO military sites and civilian critical infrastructure throughout Europe. Over the past months, Belgium, Germany, Denmark and Norway have all reported suspicious unmanned aircraft near radar stations, power facilities or airbases.

In Poland, fighter jets were scrambled in September after drones of Russian origin crossed into its airspace, an event widely interpreted as part of Moscow’s ongoing hybrid pressure campaign against Europe.

European intelligence agencies have warned that small, commercially available drones can be used for covert reconnaissance, security probing, or psychological disruption, while remaining difficult to attribute to a state actor.

No Attribution Yet

French authorities have not commented on who may be behind Thursday night’s overflight, nor whether the incident suggests broader coordination with other recent incursions across the continent.

The Île Longue base hosts France’s Triomphant-class nuclear submarines, each capable of launching ballistic missiles carrying multiple warheads. Security around the facility is among the most stringent in Europe, with continuous land, sea and air monitoring.

Officials say surveillance around the region has now been reinforced and further updates will be released once the investigation progresses.

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