French and Malian troops have regained control of the airport and bridge of the northern city of Gao.
The success marked their biggest advance yet in their bid to oust al Qaida-linked extremists who have controlled northern Mali for months, said military officials.
The move comes just two weeks after France launched its military offensive in support of the central government of this former French colony.
The French military said its special forces, which had stormed in by land and by air, had come under fire from "several terrorist elements" that were later "destroyed".
The French ministry of defence said its troops were returning the town's mayor, Sadou Diallo, who had fled to the Malian capital of Bamako far to the west.
However, a city official interviewed by telephone by The Associated Press said coalition forces so far only controlled the airport, the bridge and surrounding neighbourhoods.
And in Paris, a defence ministry official clarified that the city had not been fully liberated, and that the process of freeing Gao was continuing.
Gao, the largest city in northern Mali, was seized by a mixture of al Qaida-linked fighters more than nine months ago.
The battle to retake the city is expected to be fierece.
The rebel group has close ties to Moktar Belmoktar, the Algerian national who has long operated in Mali and who last week claimed responsibility for the terror attack on a BP-operated natural gas plant in Algeria.