Islamist rebels have taken control of the town of Diabaly in central Mali, French Defence Minister Jean-Yves Le Drian said on Monday, marking a new southwestern front four days into France's military intervention.
Le Drian said the fighting was continuing as French and Malian forces sought to drive the rebels out of the area.
"They took Diabaly ... after fierce fighting and resistance from the Malian army that was not able to hold them off at that moment," Le Drian told BFM television.
"We knew that the key spots would be towards the west and it's in the west where we were bombing last night, and it's in the west today where the most important fighting is going on," Le Drian said.
The minister earlier told reporters that French and Malian forces were battling heavily armed groups in the west, saying the area remained "a difficult spot."
France intervened in its former colony on Friday after the president of the West African nation appealed for help to halt a rebel advance south. Le Drian said France's mission could last some time and that the capital Bamako would already be in rebel hands had France not stepped in.