France launches ground assault against rebels

Despite having continually claimed that the operation would be mainly airborne and the intention was to hand over to African forces as soon as possible, President Francois Hollande vowed his forces would crush the Islamist fighters.

"What do we plan to do with the terrorists? Destroy them. Capture them if possible and make sure that they can do no harm in the future," he boasted.

After days of ineffectual air strikes on Islamist positions, French Special Forces units and Malian troops are now fighting insurgents encircled in the small town of Diabali, around 250 miles north of Bamako.

"Special forces are currently in Diabali, in close-quarter combat with the Islamists. The Malian army is also in place," a Malian security source said.

The source added that French soldiers were "on alert" in the town of Niono, 30 miles south of Diabali.

As the ground offensive got underway a French armoured detachment was also sent to secure a strategic bridge on the river Niger near the town of Markala in western Mali which leads to the capital Bamako.

Diabali was seized on Monday by fighters led by Algerian Abou Zeid, one of the leaders of al-Qaida in the Islamic Maghreb and French air raids have been unable to dislodge them.

The Islamists, who control an area in northern Mali larger than France, have retreated from many of their strongholds since the French army launched its assault on January 11.

But they claim their movements have been merely tactical.

Both Paris and experts warn the Islamist forces are better armed and trained than expected and the battle is likely to be drawn-out and complex.

French Defence Minister Jean-Yves Le Drian confirmed that troop numbers were set to triple from 800 to 2,500 men and they faced about 1,300 Islamic fighters.

At home, France has deployed 700 troops in and around Paris, indicating mounting concern over potential reprisal attacks following a Malian raid on an Algerian gas refinery.