WASHINGTON (AFP) - The United States would support a "well planned" and "well resourced" African-led force to help oust Islamic rebels in northern Mali, provided its neighbors back the idea, a US official said Monday.

"Yes, I say there will have to be at some point military action to push" the rebels linked to Al-Qaeda in the Islamic Maghreb out of northern Mali, the top US diplomat for Africa, Johnnie Carson, said.

But any such force must take its lead from Mali's army and the nation's neighbors must agree to it being set up, he told reporters on a conference call.

"Any ECOWAS military activities in northern Mali should in fact have the Malian military as the lead and ECOWAS fighting alongside of it," Carson said, summing up a whirlwind of diplomacy around African issues at the UN General Assembly last week.

"But it is not just ECOWAS. It is important that what goes on up there, has the support of all of the states in the region. The ECOWAS states as well as Mauritania, Algeria and others in the area must also be a part of this policy," he stressed, pointing to the long, porous borders that Mali shares with other nations.

"But any military action up there must indeed be well planned, well organized, well resourced and well thought through and it must be agreed upon by those who are going to be most affected by it."

Last week, Mali, France and west African nations led calls for the creation of an African-led force to help Mali flush out rebels from its northern territory seized in a March coup.

Military putschists seized power in the capital, Bamako, ousting President Amadou Toumani Toure, only to see the north and east fall to Tuareg rebels and Islamist militias linked to Al-Qaeda.

Carson stressed the need for the swift restoration of a civilian democratic government to advance progress on many of the problems plaguing the west African nation.

"If you don't have a strong credible government in Bamako it will be difficult to have a military which is capable of leading as it should the liberation in the northern part of the country," he added.

The Economic Community of West African States (ECOWAS) has 3,300 regional troops on standby to form a force, but is awaiting UN approval.