BAMAKO, Mali -- France's foreign minister said Saturday that "our African friends need to take the lead" in a military intervention to oust extremists from power in northern Mali, though he acknowledged it could be weeks before they are able to do so.

Laurent Fabius spoke to reporters on the sidelines of a closely-watched summit in Ivory Coast focusing on ways that African forces could better help Mali as France's military intervention there entered its second week.

"Step by step, I think it's a question from what I heard this morning of some days, some weeks, the African troops will take over," Fabius said in Abidjan, the commercial capital of Ivory Coast.

Neighbouring countries are expected to contribute around 3,000 troops to the operation, which is aimed at preventing the militants who rule northern Mali from advancing further south toward the capital of Bamako.

While some initial contributions from Togo and Nigeria have arrived to help the French, concerns about the mission have delayed other neighbours from sending their promised troops so far.

Ivorian President Alassane Ouattara said Saturday that Mali's neighbours must work together to eradicate terrorism in the region.

"No other nation in the world, no other region in the world will be spared" if large swaths of the Sahel are allowed to become a 'no man's land,'" he said.

At Saturday's meeting, leaders were sorting out a central command for the African force, a French official said on condition of anonymity because he was not authorized to publicly discuss the sensitive security matters.

Nigerian Gen. Shehu Usman Abdulkadir is expected to be named the force commander.

Speaking Saturday on French 3 television, French Defence Minister Jean-Yves Drian said France now has 2,000 troops in Mali and has mobilized 2,900 in the overall operation in places like Senegal, Burkina Faso and Niger.

He said France "could go beyond" the 2,500 troops initially announced for Mali, and said that at full deployment, Operation Serval would involve some 4,000 troops in the region.

Meanwhile, Le Drian insisted "there has been no ground combat in Diabaly" involving French troops,

French forces have moved around Diabaly to cut off supplies to the Islamist extremists who took the town on Monday, said a French official who spoke on condition of anonymity to be able to discuss sensitive security matters.

Mali once enjoyed a reputation as one of West Africa's most stable democracies with the majority of its 15.8 million people practicing a moderate form of Islam.

That changed last March, following a coup in the capital which created the disarray that allowed Islamist extremists to take over the main cities in the distant north.

The U.N. refugee agency said Friday that the fighting in Mali could force as many as 700,000 people to flee their homes in the coming months.