Mauritania on Monday deployed troops to seal its border with Mali where Islamic fighters are being subjected to an aerial assault by the French army, a military source in Nouakchott said.

"Our army has been redeployed along the areas bordering the fighting, with a view to better secure our country and seal its borders," the source said on condition of anonymity.

The source added that reinforcements had also been sent to the area between Bassikounou in the southeast and Kobenni, "while our aircraft have increased surveillance and control flights."

The source said the objective was to limit movement in the zone. Islamists have fled their positions in many towns targeted by the French.

French warplanes on Sunday bombed insurgent positions in the heart of the Islamic-controlled territory, in the key towns of Gao and Kidal.

France swept to action on Friday as the Islamists advanced towards Bamako, amid months of hesitation over an African intervention force.

Mauritania has ruled out participating in such an intervention, but has said its military will respond to any attacks.

President Mohamed Ould Abdel Aziz, an ex-putchist elected in 2009, has acted strongly against one of the Islamist groups Al-Qaeda in the Islamic Maghreb (AQIM), ordering cross-border raids in Mali in 2010 and 2011.

He was due to meet French President Francois Hollande on Tuesday.