French soldiers have battled Islamist militants in direct clashes on the ground in central Mali since just after landing last week, according to officials, and fighting continued on Thursday as hundreds of French reinforcements arrived. The ground battles expanded the campaign against the militants, who have seized much of the nation, beyond the airstrikes used initially.

The French defense minister, Jean-Yves Le Drian, announced on Thursday that French forces in Mali now numbered 1,400 — 600 more than the figure given on Wednesday.

“This morning there are 1,400 French soldiers on Malian soil,” he said. “There was combat yesterday, on the ground and from the air. There was more overnight and it is continuing at this moment.” He gave no details or locations for the exchanges and did not say who was involved in the fighting.