Michael Luhan, spokesman for the Organisation for the Prohibition of Chemical Weapons (OPCW), told Reuters thechemicals were under the army's control but were stored in a remote location far from the capital Tripoli, Gaddafi's main bastion.
"As far as we have been able to verify, and we have no information that indicates anything to the contrary, Libya destroyed the entire stockpile of its chemical weapons munitions - a cache of several thousand aerial bombs that are designed for chemicals - in early 2004, seven years ago," he said by telephone from the OPCW's base in The Hague.
Luhan declined to say where the mustard gas was located but added: "It's nowhere near Tripoli, let's put it that way."
"It's kept in a location which is only for that purpose. It's a depot guarded by the military."
Peter Flory, then US Assistant Secretary of Defence for International Security Policy, told Congress in April 2006 that Libyan chemical weapons and materials were stored in a remote location in the desert, about 600 km from Tripoli.
There have been fears that Gaddafi, who has said he will fight to the death, could use chemical weapons in a last ditch attempt to cling to power.
The OPCW, which enforces a global chemical weapons ban, says it has monitored Libya's destruction of more than 3,300 bomb casings designed to carry chemical agents since 2004.
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