French forces last week responded to a request from the Malian government to help thwart the advance of rebel fighters from the north of the country.
Foreign fighters who returned home from Libya last year have fought alongside militants said to be loyal to al-Qaida in the region. They helped take control over northern Mali in early 2011 after a political coup in Bamako.
U.N. Secretary-General Ban Ki-moon spoke with Ivorian President Alassane Outtara, chairman of ECOWAS, to discuss an African force for Mali.
The U.N. Security Council had approved a resolution sanctioning an African intervention. Ban, in a statement issued through his spokesman's office, said the rebel advance underscores "the urgency of implementing all aspects of the resolution, including support to ECOWAS mediation efforts."
African defense leaders told the BBC that military commanders from West African nations met in the capital Bamako to discuss pending military operations in Mali.
French airstrikes continued through the weekend. U.S. and British leaders said they were backing operations there with logistical support.
Battle lines are fluid. A resident from Timbuktu told the British broadcaster that the historic city was "free."