France's defense minister, on a surprise visit to Mali Thursday, March 7 praised the courage of soldiers driving back militants, while experts worked to identify jihadist leaders killed in battle, according to The Associated Press.

French troops launched a military operation in January to drive back the extremists marching on Mali's capital. They quickly liberated a series of cities in central Mali and are now engaged in intense battles in an area near the Algerian border that the militants hoped to make their refuge.

Jean-Yves Le Drian arrived Thursday in Tessalit, which is near the fighting in the Ifoghas mountain range. He paid his respects to the four soldiers killed in Mali so far, including one who died Wednesday.

"In dislodging the jihadists from their last bastions, you are the spearhead of this relentless war," Le Drian told troops. He also visited the Amettetai Valley, where a French soldier was killed last week.

The operation has largely been hailed a success so far, although there are some concerns the militants will simply regroup once the French start drawing down troops in April.

In recent days, Chad, which is fighting alongside France, has claimed that two major militant leaders are dead: Abou Zeid, head of one of the most violent brigades of al-Qaida's North African franchise, and al-Qaida-linked Moktar Belmoktar.

That would mark a major win in the war, but France is being cautious and hasn't confirmed the identity of the dead, although one official said Abou Zeid is likely one of them.

"You have to do stringent verifications with DNA, and that's what the army is in the process of doing," Foreign Minister Laurent Fabius said.