French troops have consolidated gains in Mali's Islamist-held north as Paris said the aim was its "total reconquest".
The French advance towards the jihadist strongholds came amid reports that the al-Qaeda-linked militants were abandoning some of their positions and converging on the mountainous region of Kidal, their northernmost bastion, 1,500 kilometres from Bamako and near the border with Algeria.
Kidal was the first town seized by an amalgam of Islamist militants and Tuareg separatist groups in March last year. The two sides then had a falling out and the Islamists have since gained the upper hand in the vast desert north.
"The goal is the total reconquest of Mali. We will not leave any pockets [of resistance]," French Defence Minister Jean-Yves Le Drian said on France 5 television.
Le Drian also said seven French citizens taken hostage by Islamist militants in Niger and Mali in recent years were alive, adding there had been "contacts with the hostage-takers".
There had been fears over their fate since the start of the French military intervention in Mali, which sparked a brazen hostage attack in neighbouring Algeria that rocked the world. The 72-hour stand-off ended in scores of deaths.
Fifty Senegalese soldiers arrived in the Mali capital of Bamako, taking the number of African troops there to 150. The planned force will comprise 5,800 soldiers, but deployment has been slow, hampered by cash and logistical constraints.
And radical Islamist group Ansaru on Sunday claimed responsibility for an attack in central Nigeria that killed two soldiers who were due to be deployed to Mali, injuring five others. Nigeria last week boosted its troop commitment for Mali to 1,200 soldiers from 900 planned earlier.
French troops on the ground, meanwhile, said they were buttressing their positions.
"The deployment towards the north … which began 24 hours ago, is on course with troops inside the towns of Niono and Sevare," Lieutenant Colonel Emmanuel Dosseur said.
Niono is about 350 kilometres northeast of the Malian capital, while Sevare is about 630 kilometres from Bamako and has a strategic airport which could serve as a base for operations.
Another town north of Niono, called Diabaly, was seized nearly a week ago by Islamists and then heavily bombed by French airplanes. Le Drian said: "Everything points to a favourable evolution of the situation in Diabaly in the coming hours."