Mali's interim President Dioncounda Traore paid a visit to French troops deployed to Bamako on Wednesday, promising them "we will win this war together", as they wage an offensive against Islamic extremists.

Traore, accompanied by west African army chiefs preparing a regional force to shore up the French offensive, visited the troops stationed at the Bamako military airport.

"Together we will win the war" against "the darkness threatening the entire world", said Traore.

He thanked his French counterpart Francois Hollande, and expressed the "gratefulness" of the Malian people for the French intervention, which was launched on January 11 as the Islamists threatened to advance on the capital.

Traore said the French presence in Mali "will open a new page in history in the relationship between Africa and the rest of the world".

Some 3,300 African troops from the region will soon arrive in Mali, and Traore urged the French and Malian soldiers to "establish good relationships with their brothers in combat."

He spoke as the French launched their first ground offensive after days of airstrikes, battling the Islamists at close range in Diabaly, 400 kilometres (250 miles) north of Bamako.