By Catherine Bremer
PARIS (Reuters) - About 15 Islamist militants were killed by French and Chadian troops in fighting overnight in northern Mali's Ametetai valley, French Defense Minister Jean-Yves Le Drian said on Tuesday.
He said some 1,600 French and Chadian troops in that area continued to search for Islamist rebels, seven weeks into a campaign to drive al Qaeda-linked fighters out of Mali's north.
"Our forces fought terrorist groups last night, still in the same area, the Ametetai valley region, where there is a strong concentration of them. Around 15 militants were killed," Le Drian told BFM TV.
"It's not over yet as after the Ametetai valley there are other valleys ... Given the ferocity of the fighting over the past fortnight, we can see there is a hideout there."
Chad's President Idriss Deby overnight reiterated that two key al Qaeda commanders, Abdelhamid Abou Zeid and Mokhtar Belmokhtar, had been killed. Le Drian, however, said France is still not in a position to confirm that they had been killed.
Deby said the two bodies had not been displayed out of respect for the dead. "I say to Minister Le Drian, who is asking for proof: as Muslims, we do not put on show the bodies of the dead," Deby said on state television late on Monday.
"In the days that come, we will see that these terrorists have indeed been killed in fighting with the Chadian forces."
Shown a photograph published in French media of a partly shrouded corpse said to be Belmokhtar's, Le Drian said it would be good news if it was the jihadist leader but that he was not convinced by the image.
Abou Zeid and Belmokhtar led the two Al Qaeda in the Islamic Maghreb (AQIM) units that operated in Mali's north, kidnapping Westerners and launching sporadic attacks over the last decade.
Three French soldiers and dozens of militants have been killed in the offensive against the Islamist fighters who hijacked a separatist Tuareg rebellion to take over northern Mali last April.
The Islamists did not fight to defend the main towns they occupied, pulling back into mountain and desert redoubts, where they have long been based and are now being hunted by hundreds of French and Chadian troops.
AQIM has pledged to avenge the French assault, which Paris says it launched due to fears that its former colony could become a launchpad for wider Islamist attacks.
Asked about the risks of the fighting to a French family taken hostage in Cameroon last month by Islamist militants and taken into Nigeria, Le Drian said France had information on the whereabouts of the three adults and four children, and everything indicated they were still alive.
"I think if the hostages had been killed, their captors would have let it be known," he said. "We are using all the means we can to get them freed."
(Additional reporting by Madjiasra Nako in N'Djamena; Editing by Louise Ireland and David Lewis)