France calls for military help as rebels flee to mountains

But reports indicated the rebels were leaving their strongholds for the mountainous Kidal region, near the Algerian border.

"They are fleeing. All indications show that they are seeking refuge in Kidal, which is difficult to access," a Malian official said.

France launched a military offensive on January 11, which was initially restricted to air strikes before ground troops arrived and halted the rebels' assault into the government-controlled south.

But the country is becoming increasingly vocal about the lack of support for its operation.

More than 2,000 French soldiers are now in Mali and there were rumours the initially 2,500 figure may be raised to 4,000.

That could be a financial struggle for France, despite President Francois Hollande's claims that it would do whatever it takes.

While many Western states have offered logistical support, none have put up military aid.

And African troops have been slow to come forward, largely for economic reasons.

West African leaders sought urgent UN aid at an emergency summit of the regional Ecowas group on Saturday.

Ecowas called on its members and Chad, which has pledged 2,000 soldiers, to hurry up.

Only about 100 African soldiers of a planned 5,800 have so far reached Mali.

French Foreign Minister Laurent Fabius said it was time for the Africans to take charge of the task of halting the extremist advance "as soon as possible."