A surveillance drone followed eight "members of an armed terrorist group" as they crossed the border on motorcycles from Niger into Mali, Colonel Patrik Steiger said.

A French fighter jet attacked the group, with ground forces then intervening, in an operation that claimed the lives of at least six of them, he added

Jihadists in the region have mostly swapped pick-ups for more inconspicuous motorbikes, which allow them to travel on rough roads and tracks through the desert.

The operation revealed however that even these bikers are being monitored from the air.

The French military did not specify which jihadist group the men belonged to but a regional Al-Qaeda affiliate has long been active in the region.

France helped Malian forces defeat jihadist insurgents that took control of the three main towns in the country's north in 2012, but large swathes of the hinterland remain beyond the government's control.

France, the former colonial ruler, has deployed a 4,500-member 'Barkhane' force in the region to conduct counter-terrorism operations.

Until now the force has intervened mainly in Mali, while also focussing on training troops in Burkina Faso and the other nations of the G5 Sahel military alliance -- Chad, Mauritania and Niger.

However, the insurgents have progressively expanded their reach, carrying out attacks on government forces, notably in Burkina Faso and Niger.