An unidentified drone has been spotted flying over a sensitive military site near Paris, France.
It is the latest in a series of similar incidents that have been reported in the city.
According to the Daily Telegraph, a small drone made two flights over the Sainte-Assise naval communications centre, which is used for the command and control of submarines.
The centre is equipped with 200m antennas and a transmitter to communicate with French Navy submarines at sea.
A local police official was quoted by the newspaper as saying: "This is the first time we’ve faced this type of situation."
Following the incident, a police helicopter was sent to the site, but failed to identify the operators.
Meanwhile, Le Parisien newspaper has reported that one or several drones had flown over the centre earlier and claimed that one had crashed at the site.
Drones have recently been spotted flying over several sites in Paris, including the Eiffel Tower, the American embassy, the Louvre museum and the presidential palace.
French Interior Minister Bernard Cazeneuve said that at least 60 sightings have been reported at sensitive sites over the past five months.
A police official was quoted by the Telegraph as saying: "Flights like this would yield little or no useful intelligence in terms of surveillance with a view to planning an attack."
Drone flights without permission are illegal in France and carry a maximum penalty of a year in prison and €75,000 fine.