A picture taken on December 5, 2016 shows a nuclear submarine at the naval base in Ile Longue, western France. FRED TANNEAU / AFP

The French military used anti-drone measures after five unmanned vehicles flew over a closely guarded base housing nuclear ballistic submarines, a source told AFP on Friday, December 5. The drones were detected above the base on Ile Longue, a peninsula off the Brittany coast in northwestern France, at around 7:30 pm local time Thursday, said the source close to the operation.

An anti-drone and search operation was launched by the marine battalion, which protects the base, the source said. It was not immediately clear what those measures entailed.

A judicial investigation into Thursday's incident was to be opened by the military prosecutor's office in Rennes, the Atlantic Maritime Prefecture told AFP. "Sensitive infrastructure was not threatened," Guillaume Le Rasle, spokesman for the maritime prefecture, told AFP. He said it was "too early to determine" the origin of the drones, adding however that those flights were "intended to cause concern among the population."

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