PARIS

Three Aljazeera English journalists arrested on suspicion of flying a drone over Paris have been released, police officials have said.

One of the three who was allegedly controlling a device will be summoned to court next week, police officials said on Thursday.

The three foreign nationals, aged 34, 52, 68, were detained on Wednesday after being spotted by police as they were allegedly flying a drone in the Bois de Boulogne woods in western Paris.

The arrests came after a series of unidentified drones were spotted flying over key landmarks such as the Eiffel Tower, the Place de la Concorde, the Invalides military museum and La Bastille in the capital on Monday and Tuesday nights.

 Paris has been on a high security alert following the attacks on the offices of satirical magazine Charlie Hebdo and a kosher supermarket in early January.

Aljazeera said in a statement the three were arrested and questioned by Paris police "while filming a report on the city's recent mystery drones".

Flying drones in French airspace requires authorization from the Defense Ministry and the Regional Directorate of Civil Aviation (DGCA), while flying a drone at night is illegal, with violators facing up to a year in prison and fine of up to €75,000 ($85,000).

Other unidentified drones have been spotted in French skies in recent months.

A drone briefly flew over the presidential palace in Paris on Jan. 20, while another 20 were spotted above nuclear power plants in northern and southwestern France in October and November last year.

Under French law, civilian drones are banned from areas such as nuclear facilities, which are protected by no-fly zones.