MISRATA:  Seven months after Libyan forces defeated Islamic State in the coastal city of Sirte, hundreds of bodies of foreign militants still lie stored in freezers as authorities negotiate with other governments to decide what to do with them, local officials say.

The corpses have been shipped to Misrata, a city further to the west whose forces led the fight to defeat Islamic State in Sirte in December.

Allowing the bodies to be shipped home to countries such as Tunisia, Sudan and Egypt would be sensitive for the governments involved, wary of acknowledging how many of their citizens left to fight as jihadists in Iraq, Syria and Libya.

"Our team removed hundreds of bodies," a member of the Misrata organised crime unit dealing with the bodies told Reuters, his face masked to conceal his identity because of security concerns.

"This is the main operation which allows us to preserve the bodies, document and photograph them and also collect DNA samples."

The crime unit said it was awaiting a decision from the Prosecutor General, who was in talks with foreign governments over the return of the bodies.

Islamic State has now been defeated in its main stronghold in the Iraqi city of Mosul and is under pressure in its base in the Syrian city of Raqqa. But at the height of its territorial control it attracted recruits from the Middle East, North Africa and Europe to its ranks.

In Tunisia alone, officials say more than 3,000 citizens left to fight in Syria, Iraq and Libya. Tunisians who trained in militant camps in Libya carried out two gun attacks on foreign tourists in 2015 that battered Tunisia's vital tourism industry.

Islamic State took over Sirte in 2015, taking advantage of infighting between rival Libyan armed factions and using the city as a base from which to attack oil fields and other nearby towns.