Fears over Libya's missing missiles
Concern has been mounting over the fate of weapons stockpiles accumulated during the rule of fugitive Libyan leader Col Muammar Gaddafi, many of which have been looted, or are left unguarded in warehouses.
Col Gaddafi and his loyalists built up extensive armouries during his four decades in power.
But now, six months after rebel forces took up arms against him, most of these sites lie abandoned after they were overrun in battles, or as troops guarding them fled.
This week, journalists in and around the Libyan capital, Tripoli, have reported visiting buildings containing missiles, grenades, rockets and mines - all unsecured.
In one site, Peter Bouckaert from the campaign group Human Rights Watch, says he found 100,000 anti-tank and anti-personnel mines.
But it is the empty boxes and containers which have sparked bigger fears.'Destabilising risk'
While Libyan rebels have taken some of the weapons in recent months to arm their conflict against forces loyal to Col Gaddafi, it is unclear where the rest have ended up.
Most notably, some empty boxes seen by reporters were marked as having held 9M342, which experts linked to the SA-24 Grinch, a Russian surface-to-air missile (SAM).
"All of Libya is a grand arms bazaar," says Mr Bouckaert, who says it appears that SA-14 and SA-7 missiles have also been taken.
Speaking to the BBC from Tripoli, Mr Bouckaert said the rebels have no use for SAMs anymore, given that there is no longer a threat from the air, but that they were still going missing - and were often the first to go.
"It begs the question - why are these being so sought out?" he said.
He said Col Gaddafi had had a "vast arsenal" of some 20,000 SAMs, of which much had gone. "It seems to be one of Gaddafi's favourite toys."
Such weapons, Mr Bouckaert adds, would be "capable of bringing down a civilian aircraft".
"These are the kind of weapons that groups like al-Qaeda, and Iran and other countries, want to get their hands on, for the technology," he said.
US and UN officials have urged the rebels to secure the sites, saying they risk destabilising the entire region.
In a speech in Paris last week, US Secretary of State Hillary Clinton expressed concern that weapons could be sold to Islamist groups on the black market.
End Quote Peter Bouckaert Human Rights Watch
Many of the most dangerous weapons have been taken. So it's too late”
"Libya's new leadership will need to continue to stand against violent extremism and work with us to ensure that weapons from Gaddafi's stockpiles do not threaten Libya's neighbours and the world," she said.
Ahmed Darrat, who is overseeing the interior ministry for the rebels, downplayed the threat, saying the threat of extremism was merely scaremongering.
"Saying that there are armed extremists in Libya is what Gaddafi used to say," he told AFP news agency.
But Libya's geography leaves it vulnerable to such concerns, with al-Qaeda in the Islamic Maghreb (AQIM) - an off-shoot of al-Qaeda - active in neighbouring countries such as Niger, Mali and Algeria.
On Wednesday, the EU's counter-terrorism coordinator, Gilles de Kerchove, said it was possible that AQIM had already acquired some of Libya's weapons, including the surface-to-air missiles.
Others have disputed his comments, with French Defence Minister Gerard Longuet saying measures were in place to prevent the spread of armaments.Mustard gas
However, it is quite feasible that weapons have crossed Libya's borders. And some weapons sites may still remain, undiscovered, in Libya.
As Nato targeted a number of sites believed to be storing weapons, Col Gaddafi's guard moved many caches to civilian buildings.
But it is not just an outside threat that is worrying; for many analysts, the more likely possibility is the spread of arms to various groups within Libya itself, at a time when the National Transitional Council is struggling to reassert order.
Various observers warn that a plethora of weapons could leave Libya open to civil war in the future.
"It is a worry and needs to be secured. Failure to do so in Iraq made the insurgents and militia quartermasters' jobs a lot easier," said Benjamin Barry, a senior fellow for Land Warfare at Britain's International Institute for Strategic Studies.
"The NTC ought to be able to work out for themselves that the greatest threat posed by these unguarded dumps is the security and stability of Libya," he told Reuters news agency.
Mr Bouckaert says the danger for Libyans is the "the vast amount of explosive weapons that are available", such as mortars and tank shells.
"That's what destabilised Iraq and Afghanistan so much - the IEDs (improvised explosive devices)".
Meanwhile, the discovery of gas masks in some sites in Libya has also raised questions about the quantity and whereabouts of Col Gaddafi's chemical weapons.
In 2004, in the wake of the invasion of Iraq, Col Gaddafi agreed to dismantle weapons of mass destruction following secret talks with the US and UK.
As part of his commitment, he deployed bulldozers to crush 3,300 unloaded aerial bombs that could have been used to deliver chemical weapons, and agreed to destroy his stores of mustard gas.
The Organisation for the Prohibition of Chemical Weapons (OPCW), a UN watchdog, says nearly 40% of the chemicals used to make mustard gas have been destroyed since 2005.
Earlier this week, OPCW Director General Ahmet Uzumcu said he had been assured from sources that the "remaining stockpiles of chemical weapons" were safely secured.
His organisation has not been in Libya since February, he said, but it is now preparing to send more inspectors to investigate.
Mr Bouckaert says officials on Thursday agreed to move the unsecured weapons to new facilities, but said he believed that most of the damage had already been done.
"Once they're gone, they're gone. Many of the most dangerous weapons have been taken. So it's too late."