Western and Arab security specialists say they fear jihadists who have taken over northern Mali will turn it into a base for Islamist terrorism across the Sahel region and Western Europe.

Much will depend on whether Mokhtar Belmokhtar, a veteran jihadist and one of the deadliest leaders of al-Qaida's North African wing, is dead or alive.

Belmokhtar, an Algerian dubbed "the uncatchable" by French Intelligence, was reported killed June 25 in the battle for Gao in northern Mali between Tuareg separatists and the Islamists of the Movement for Unity and Jihad in West Africa.

If Belmokhtar, 40, has been slain, the jihadists have lost a resourceful and seasoned leader who's built up a network of alliances across the vast region over the years. He achieved this in part by marrying four female relatives of Arab and Tuareg tribal leaders who give him safe haven and logistical support.

His main sources of revenue is kidnappings for ransom and providing security for smugglers moving Central American narcotics from the West African coast across the Sahara en route to Europe.

The Algerians, who've been fighting Islamists since 1992, put a large bounty on his head. These days the French, the Americans and others are also gunning for him.

But, as the Jamestown Foundation, a Washington think tank that monitors terrorism, observes, "Belmokhtar appears to have successfully woven himself into the fabric of the region."

His regional links and tactical skills are vital for any jihadist group seeking to establish a haven in the Sahel, the semi-arid belt below the Sahara that runs across northern Africa from the Atlantic to the Red Sea.

Algerian sources claim Belmokhtar, the Algerian Islamists' chieftain in the south for two decades, was indeed killed. There's been no reliable confirmation of that but accounts of his death in battle vary only in the details.

Al-Qaida in the Islamic Maghreb denies he was slain but has yet to provide conclusive evidence he's alive.

On June 28, AQIM issued a communique under his nom de guerre of Khalid Abu al-Abbas but Jamestown observed that none of the events it described established beyond doubt that he'd survived.

"If he has been killed, AQIM has lost one of their most effective leaders, even if he has seemed for some time to be waging his own personal war and devoting much of his energy to lucrative criminal enterprises," a well-informed French security source said.

It's not clear to what extent this could undermine the jihadist successes in northern Mali that were triggered by the anarchy that followed the fall of Libya's Moammar Gadhafi in August 2011.

But the upheaval stirred by the Libyan war and the dispersal of Gadhafi's North African mercenaries with large amounts of plundered weapons is causing increasing alarm across the region, and beyond.

The Economic Community of West African States wants to send in a 3,000-strong military force to stabilize northern Mali before the jihadists can consolidate.

It already may be too late. Besides, ECOWAS' military capabilities are extremely limited.

Outside intervention would probably be more effective. But that would likely ruffle regional feathers, particularly with the Algerians, who especially don't want the French, their former colonial masters, involved.

Still, the Financial Times observed: "Africa should not be left alone to sort of this mess, which is a consequence of partly of the fall of Col. Gadhafi's regime in Libya last year.

"Security does not start on the French Riviera. European leaders in particular should wake up to the threat posed to their turf by a lawless region populated by terrorists and drug traffickers to the south."