Thousands of surface-to-air missiles pillaged in Libya pose less of a risk than feared as most militant groups in sub-Saharan Africa lack the knowhow and the equipment to fire them, experts say.

The Soviet-made SA-7 is a man-portable low-altitude missile with a high explosive and passive infrared homing device that could pose a nightmare in the Sahel where an Al-Qaeda affiliate, among other groups, is active.

While some fear they could be used to target commercial flights if they fell into the wrong hands, others say that using them is not so simple and that they could turn out to be just scrap metal, if not properly stored.

The arsenal of toppled Libyan strongman Moamer Kadhafi comprised about 20,000 such missiles, initially manufactured in the former Soviet Union since 1972 and then in other east European countries, according to experts.

Several informed sources said many of them had found their way to clandestine markets in sub-Saharan Africa, where they could be offered to groups such as Al-Qaeda in the Islamic Maghreb.

"We have got wind of the fact that they are looking for instruction manuals in Arabic," a French anti-terrorism expert told AFP on condition of anonymity.

"But there is nothing to indicate that these missiles are in a functional state. And using them is more difficult than it would seem."

Another expert, also speaking on condition of anonymity, said: "We know that Tuareg arms traffickers have got their hands on Libyan SA-7 missiles. But they are going to have serious maintainence problems."

"For a start, these missiles can only be used with thermal batteries, which need to be recharged. We do not think AQIM has the necessary networks to get these."

The cylindrical 9B17 thermal battery allows the seeker to track the target by detecting infrared radiation and then hit targets up to an altitude of 4,500 metres (14,850 feet).

The missiles and batteries are usually stored separately.

Following Kadhafi's ouster, journalists who were able to access some of his armouries saw empty missile crates with their contents looted, but the batteries had been left behind.

A top US general recently said the United States and the international community believe Libya's new rulers are responsible for preventing weapons proliferation in a region battling terrorism.

General Carter Ham, the head of the Africa command, Africom, said there was "a threat of the proliferation of the weapons from Libya and we are greatly concerned ... about small arms, rifles and weapons similar to that, but also explosives and shoulder-fired air defence systems."

Nearby Algeria, Mali, Mauritania and Niger -- all large but mainly poor countries -- are prey to attacks by AQIM, which is battling the military in the Sahel nations, has taken Western hostages and is held to be engaged in arms trafficking.

Matthew Schroeder, the manager of the Arms Sales Monitoring Project at the Washington-based Federation of American Scientists, downplayed the fears of the missiles wreaking havoc.

"These missiles have in theory a shelf life of 10 to 20 years. But lots of these missiles are old, some may not function properly. And if they are not handled properly, they can be damaged," he said.

"It's not good for these weapons to be taken out of their crates and thrown in the back of a truck. It's not like an AK series rifle, you know."

And using them was not child's play, he said.

"They do require some training. It's not as simple as it's often portrayed. If you're a trained operator, it's not complicated, but specially with the older ones, in order to be reasonably confident you're going to hit the target you've got to know what you are doing."

In July last year, he wrote an article for the specialised magazine Foreign Policy entitled "Stop Panicking About the Stingers" in which he tried to calm fears that insurgents in Afghanistan, who had got hold of the heat-seeking missiles, could use them against US planes.

"In the recent conflict in Afghanistan, I don't know of any report of a Stinger missile used since 2001," he said. "I don't know of any downed plane as a result of Stingers. It also depends on the storage conditions."