The French military used jammers as several suspected drones flew over a closely guarded base housing nuclear ballistic submarines, prosecutors said on Friday.
It was the latest in a series of mysterious drone flights over airports and sensitive military and industrial sites across Europe.
Three-and-a-half years into Russia’s invasion of Ukraine, there is growing concern that such disruption could be part of hybrid war tactics by Moscow against the European Union, which has backed Kyiv.
No drones were shot down and no pilots were identified during the flyover on Thursday evening at the submarine base on Ile Longue, a peninsula off the Brittany coast in northwestern France, prosecutors said as they opened an investigation.
“No link with foreign interference” had been established at this stage, prosecutor Frederic Teillet said.