Algerian jihadists are reported to have reinforced Islamist fighters linked to al-Qaida in their self-declared state in northern Mali amid signs the conflict there may be spilling over across the drought-hit region spanning North Africa.

A band of about 30 Algerians, all fighters from the Algeria-based al Qaida in the Islamic Maghreb, arrived in the town of Gao last week to join the extremist Muslim group known as the Movement for Oneness and Jihad in West Africa, regional security sources reported.

The seasoned AQIM fighters, veterans of an insurgency in Algeria that began in 1992, sought to link up with one of AQIM's top commanders, Mokhtar Belmokhtar.

He heads the group's southern forces in the Sahara Desert. Security sources said he's been in Gao, held by MUJAO and the main Islamist group, Ansar al-Dine, since a Tuareg revolt in northern Mali in March.

Gao and other towns in the arid wastes of northern Mali, an area the size of France, were overrun by Tuareg secessionists of the National Movement for the Liberation of Azawad, the tribesmen's name for the region which they have for decades sought to make an independent state.

The secular MNLA, with an estimated 10,000 fighters, was aided by Ansar al-Dine's jihadists and its Islamist allies who between them muster around 800 men.

The emergence of an Islamist territory in North Africa underlined a growing alliance between AQIM, which seeks to create a jihadist alliance across North Africa and even south into oil-rich Nigeria, and its Islamist allies.

The conquest of northern Mali, the first involving Islamist forces, was triggered by the Libyan war, which has destabilized the impoverished, largely desert region.

Tuareg tribesmen who fought for Moammar Gadhafi plundered his armories when he was defeated and took to the desert with heavy weapons rarely seen in insurgent hands in the volatile region.

Both Malian Islamist groups, funded by AQIM, have been recruiting foreign fighters in the Sahel and, security sources say, as far afield as Pakistan.

This is causing grave trepidation across the region, particularly in Algeria, North Africa's military heavyweight which considers itself a key bastion against militant Islam.

"The crisis in Mali and the outflow of refugees is destabilizing the whole region," observed Andrew McGregor of the Jamestown Foundation, a Washington think tank that monitors international security.

Algeria "has been urged by some Western and regional nations to take a leading role in any intervention, but appears reluctant to provide ground forces.

"Algeria's participation is widely viewed as the key to success for any military intervention."

That's because the Algerians, who fought a decade-long war against Islamic extremists from 1992, have the firepower and considerable combat experience fighting insurgents in the desert.

But Algiers refuses to allow Western forces, particularly troops from the former colonial power France, to get involved in regional counter-insurgency operations.

Right now, the only regional intervention under discussion is a military incursion by forces from the 15-state Economic Community of West African States.

But the government in Bamako, Mali's capital where the political situation remains fragile, is opposed to any outside intervention at this time.

With its military fragmented and demoralized after being whipped by the MNLA's Tuareg fighters and their erstwhile Islamic allies, there seems little prospect Bamako will seek to retake the north any time soon.

"There are threats incubating in northern Mali's desert that have the potential to spill over into the borders of ECOWAS states or Algeria -- or to target transnational interests -- and the growth of those threats will determine if or when outside powers become more actively engaged in the conflict," observed the global security consultancy Stratfor.

The bond between the MNLA and the Islamists was never strong and after the northern state was proclaimed, the Islamists broke with the MNLA. They've clashed several times with dozens of casualties.

The MNLA, which has a more moderate and tolerant Islamic base, opposes introducing Muslim religious law and fears the excesses of the jihadist groups could alienate a population that's shown little enthusiasm for their new rulers.

Indeed, McGregor observed that "there are many indications that those northern Malians who have not fled the country outright are already tired of Islamic rule" and are mounting protest demonstrations.

"It's now clear that the MNLA is now trying to distance itself from the Islamist factions."