In a statement sent to reporters, the Army Ministry said the missiles were intended for the "self-protection of a French military unit deployed to carry out counterterrorism operations."
"They were not transferred to local forces," the statement said.
"Damaged and unusable, the armaments were being temporarily stocked at a depot ahead of their destruction," the ministry said.
The New York Times reported earlier that the cache of four Javelin anti-tank missiles were recovered last month by Libyan government forces during a raid on a rebel camp in the town of Gheryan, in the mountains south of Tripoli.
Libyan commander Khalifa Haftar, whose forces hold eastern Libya and much of the country's south, launched an offensive in early April to wrestle the capital from forces loyal to the U.N.-recognized Government of National Accord (GNA).
Airstrikes and ground fighting have since left nearly 1,000 people dead and some 5,000 wounded, the U.N.'s World Health Organization said last week.
The fighting has forced more than 100,000 people to flee their homes and threaten to plunge Libya into deeper conflict.
Libya has remained beset by turmoil since 2011 when a bloody NATO-backed uprising led to the ouster and death of long-serving President Muammar Gaddafi after more than four decades in power.
Since then, Libya's stark political divisions have yielded two rival seats of power -- one in Tobruk and another in Tripoli -- and a host of heavily armed militia groups.
World powers have been divided over how to respond to Haftar's offensive, with the United States and Russia refusing to condemn the Libyan strongman. The GNA receives support from Turkey and Qatar, and Haftar is backed by the United Arab Emirates, Egypt, and according to experts, to some degree by the United States.
