French troops killed 19 extremist militants during an army operation in Mali’s rebel-infested northern desert on Tuesday, a French military source told media outlets.

French troops killed 19 extremist militants during an army operation in Mali's rebel-infested northern desert on Tuesday, a French military source told media outlets.

"A French military operation is underway north of Timbuktu. French troops are facing a pretty determined group. At the moment, 19 members of this group have been killed," the Bamako-based source said.

"The French troops haven't reported any deaths or injuries. We are in control of the situation."

A French-led offensive in January drove extremist groups linked to Al-Qaeda out of the cities of northern Mali, including Timbuktu, Gao and Kidal, after they occupied them in the wake of a coup in Bamako last year.

But the so-called jihadists have continued to launch periodic strikes on the French, Malian and African peacekeeping forces.