The thought of al Qaeda's Sahara wing getting its hands on Libyan surface-to-air missiles is chilling for the West. But a new flow of small arms and return of battle-hardened fighters may pose the bigger regional threat.
The fall-out southwards from the civil war in the North African country has so far been mainly limited to waves of returning migrant workers.
But governments in the Sahel believe fighters of al Qaeda in the Islamic Maghreb (AQIM) have received convoys of weapons including SA-7 missiles looted from Libyan leader Muammar Gaddafi's abandoned arms caches.
Targeting airliners would take training and moving al Qaeda cells nearer cities, so experts believe any heavy weapons are more likely to be used defensively in case of airborne attacks on the Islamist militants.
However the remote and often volatile corners of countries such as Mauritania, Mali and Niger, where Islamists operate alongside rebels, local criminals and smugglers, are extremely vulnerable to the spillover effects of Libya's conflict.
"The situation in Libya poses quite some problems for West African countries," said Kwesi Aning, a senior official at the Kofi Annan International Peacekeeping Training Centre in Ghana.
"It is natural that some of the weapons would get into very bad hands ... There is no government control in the northern parts [of the Sahel fringing Libya]," Aning said.
AQIM emerged out of the Algerian Salafist movement in 2007 and, under pressure from the Algerian army to the north, has become increasingly active in the Sahara region.
The group, believed to number no more than a few hundred, has taken advantage of poor cross-border coordination to mount sporadic attacks on local armies and kidnap Westerners, earning some $50-70m in ransoms so far, analysts say.
A recent flurry of regional diplomacy has underscored pressing concerns over a spillover from Libya. Fears of a reprisal after the killing of Osama bin Laden are also high.
The leaders of Mali and Chad believe looted weapons have reached AQIM bases in northern Mali, with Chad's president warning they could become the best-equipped force in the region. An Algerian official spoke of several convoys.
Others say there is no proof yet, though few think it would take much for AQIM, which is plugged into weapons smuggling networks and flush in cash from ransoms, to obtain them.
"There are enough floating around that it would be extremely easy for people keen to get hold of them to do so," said Peter Bouckaert, emergencies director at Human Rights Watch, who has spent weeks documenting the looted arsenals in Libya.
Much of the focus has been on missing SA-7 shoulder-launched missiles, used by al Qaeda operatives who tried, but failed, to shoot down an Israeli charter plane in Kenya in 2002.
"It is a top concern because this is one of the favourite weapons of al Qaeda groups," Bouckaert said, noting that militants in Iraq showed how stolen weapons could also be turned into bombs.
Officials are acutely aware of the threat and fears of a "spectacular" attack in retaliation for the killing of bin Laden are real, but due to their short range, SA-7s would have to be moved by militants from remote desert bases to near airports by major cities if airliners were to be targeted, experts say.
"They are probably more useful as defensive weapons," said one diplomat who monitors the group's activities.
After mostly opportunistic kidnappings, attacks this year in Niamey and Nouakchott have proven AQIM's ambition to hit capital cities. But another hurdle is the weapon itself, according to Nick Pratt, a terrorism expert at the George C Marshall European Center for Security Studies.
"It is not a weapon you just pick up and shoot... The big issue is that it takes a long time to train," said Pratt, whose military experience included taking part in covert US efforts to arm Mujahideen guerrillas in Afghanistan.
"Old Soviet-era [missiles] in the Sahara are less of a security concern than a truckload of AK's [assault rifles]."
It may not just be the weapons that flow south either.
There are widespread reports of Gaddafi recruiting fighters, especially Tuareg nomads, to swell his ranks. Some of these new recruits, as well as fighters from the region who had long been in his ranks, will return home one day, officials say.
Similar flows of experienced fighters back into marginalised parts of Mali and Niger were factors in rebellions during the 1990s. These countries' governments are still struggling to heal wounds after the most recent uprisings between 2007 and 2009.
"There is something of a historical pattern we don't want to repeat," said Andre LeSage, Africa expert at the US-based National Defense University.
Northern Mali, with its grinding poverty and isolation, is particularly susceptible. AQIM has turned it into a rear base, integrating into local tribes through marriage and seeking to drive a wedge between the government and local populations.
Profitable smuggling networks also zigzag through the barren zone, undermining law and order and fuelling corruption.
Mali President Amadou Toumani Toure last week sought out support among community leaders, warning them of the risks of the flow of weapons and fear of AQIM recruiting new fighters.
"We need community leaders to be on good terms with national governments so there isn't popular support for any movement ... so they don't gain traction," LeSage said.
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