BAMAKO, Mali — French special forces inched closer to an Al Qaeda-held town, fighting erupted in another center, and army troops raced to protect a third, as the Islamist extremists controlling northern Mali ceded no ground Thursday, digging into the areas they already ­occupy and sending out scouts to widen their reach.

Banamba, a town 90 miles from the capital, Bamako, was put on alert overnight and a contingent of roughly 100 Malian soldiers sped there on Thursday after a reported sighting of jihadists in the vicinity, the closest the extremists have come to the seat of government of this West African country, officials said.