Hundreds of jihadists poured into northern Mali over the weekend to help armed Islamist groups hang on to the territory as the country's neighbours speeded up efforts to try to wrest control of the vast desert region from the Al-Qaeda linked militants.

Residents of the cities of Timbuktu and Gao, Malian security officials and Islamist commanders all confirmed that there had been a huge influx of foreign fighters over the past two days.

"In the Timbuktu region and around Gao, hundreds of jihadists, mostly Sudanese and Sahrawis, have arrived as reinforcements to face an offensive by Malian forces and their allies," a Malian security official said on condition of anonymity.

One resident of Timbuktu said "more than 150 Sudanese Islamists arrived in 48 hours".

"They are armed and explained that they had come to help their Muslim brothers against the infidels," he said.

The influx comes as the west African regional bloc ECOWAS forged on with plans to try and reconquer northern Mali amid fears that the area will become the same type of sanctuary for radicals that Afghaistan was a decade ago.

Mali's former colonial power France said that it had resumed military cooperation with the country, which it had cut off following the March coup that created the conditions allowing armed Islamist groups to take over the country's sparsely-populated north.

"In principle, the decision has been taken to respond to the needs of the Malian army in terms of  what is necessary," including sending military advisors, Jean Felix-Paganon, Paris's special envoy for the Sahel, told AFP late on Sunday.

France has offered logistical support for the 3,000 strong force that ECOWAS has assembled to try and drive out the radicals.

On October 13, the UN Security Council gave ECOWAS 45 days to come up with a detailed plan of how it intended to recapture the vast, sparsely populated terrain.

 'They want war, we'll give them war'

On the ground in northern Mali, Islamist fighters were reported to have been arriving in droves since Friday in the main cities of Gao and Timbuktu.

"They want war, we'll give them war. This is why our brothers are joining us from all over," told AFP Habib Ould Issouf, a top leader of the group that controls Gao, Movement for Oneness and Jihad in West Africa (MUJAO).

"They are coming from the camps of Tindouf in Algeria, from Senegal, from Ivory Coast, from everywhere," he said.

One resident said he had seen around 10 pick-up trucks packed with armed fighters driving up to the group's headquarters in the city.

The chaos in Mali began on March 22, army officers toppled the government in protest at what they said was its failure to equip them to counter a burgeoning rebellion by Tuareg separatists and their Islamist allies.

But the ensuing power vacuum allowed the rebels to sweep through the sparsely-populated desert region and establish control over an area roughly the size of France.

The Islamists quickly sidelined their former Tuareg allies and established their version of Islamic law, amputating the hands and feet of thieves and stoning unwed couples, in addition to destroying revered Muslim shrines that they consider blasphemous.

In the south, the officers who led the coup handed over to an interim administration, but retain considerable influence.