French troops are set for their first major ground combat with Islamist rebels in Mali after heading out from the capital, Bamako, reports the BBC.
A convoy of about 30 armoured vehicles set out on Tuesday for Diabaly, 350km (220 miles) to the north, a town captured by the rebels on Monday.
The first units of an African force are set to arrive on Wednesday to bolster the French.
France intervened last Friday to halt the Islamists' drive to the capital.
Islamists entered Diabaly on Monday, taking the town from Malian forces.
French war planes have since attacked the rebel positions.
French Defence Minister Jean-Yves Le Drian confirmed on Wednesday that French troops had headed north.
The BBC's Mark Doyle in Bamako says the convoy of armoured personnel carriers set out with guns at the ready; at some points along the road, people gathered to wave at the French soldiers.
Mr Le Drian has admitted that Malian forces around Diabaly have been struggling to combat well-armed rebels.
He also admitted that the central town of Konna had not been recaptured by government forces as had earlier been reported.
He said: "We are up against a determined adversary that is well-equipped and has not given up, but we have hit them hard with our strikes, including those deep in their territory."
Read more of this report from the BBC.