BAMAKO, Mali – After a punishing bombing campaign failed to halt the advance of al-Qaida-linked fighters, France pledged Tuesday to triple the size of its force in Mali as it prepared for a land assault to dislodge the militants occupying the northern half of the country.

The move reversed France’s earlier insistence on providing only aerial and logistical support for a military intervention led by African ground troops.

France plunged head-first into the conflict in its former colony last week, bombarding the insurgents’ training camps, arms depots and safe houses in an effort to shatter the Islamist domination of a region many fear could become a launching pad for terrorist attacks on the West and a magnet for extremists from around the world.

Despite five days of airstrikes, the rebels have extended their reach, taking over a strategically important military camp in the central Malian town of Diabaly on Monday.

On Tuesday, France announced it was increasing the number of troops from 800 to 2,500. The offensive was to have been led by thousands of African troops pledged by Mali’s neighbors, but they have yet to arrive.

French President Francois Hollande said Tuesday that he believed France could succeed in ousting the extremists in a week, but there also would be a longer-term commitment. “We have one objective: To make sure that … when we end this intervention, there is security in Mali, legitimate leaders, an electoral process and the terrorists no longer threaten its territory.”