French authorities have been left puzzled by sightings of at least five unexplained drones flying over Paris.
According to Sky News, the first drone was spotted in the skies above the US embassy in the early hours of Tuesday morning, a security source said.
Others were later seen over the Eiffel Tower and the Place de la Concorde.
Their appearance marked the latest in a series of unexplained drone sightings across France.
A security source said there have “never been so many drones appearing in one night”.
Despite stepping up security measures in the wake of anuary’s Charlie Hebdo Attacks, authorities have been unable to identify the operators of the drones – including those seen last night.
“It could be a coordinated action but we don’t know for now,” the source said.
“We did everything to try and catch the operators but they were not found,” another source close to the investigation added.
Last month a pilotless aircraft was spotted over the presidential palace in Paris.
There have also been reports of dozens of drones flying over French nuclear power plants in recent months.
In France it is illegal to fly small civilian drones over sensitive areas like nuclear facilities.
They are protected by a no-fly zone that spans a 1.6-mile radius to a height of 1,000 metres.