PARIS: Around 15 Islamic militants were killed overnight in heavy fighting with French and Chadian forces in northeastern Mali, French Defence Minister Jean-Yves Le Drian said Tuesday.

The defence ministry has said dozens of Islamists have died in the area over the past few days. A third French soldier died in the conflict on Saturday.

"There were operations carried out by our troops overnight against a group of terrorists in the region, in the Ametettai valley," Le Drian told BFMTV, adding that there were "around 15 killed".

French-led forces launched military operations in Mali in mid-January seeking to drive out radical Islamists who had controlled the vast desert north of the country for nearly a year.

The offensive quickly routed the Islamist fighters from main cities and fighting has since been concentrated in the rugged mountain terrain in the northeast.