Libyan air force launch operation to trap IS fighters

War planes from Libya's unity government launched an operation Saturday to cut off potential escape route for Islamic State group fighters holed up in the coastal city of Sirte.

The forces of the Government of National Accord said on their Facebook page that a surveillance operation covered central Libya as well as the western region up to the border with Tunisia.

Pro-government forces - backed since early August by US air strikes - began an assault in mid-May to expel IS from its Sirte stronghold.

They fought their way into the city on 9 June but were slowed down by a barrage of sniper fire, suicide bombings and booby traps.

After steady advances the armed group are pinged between the downtown area and the sea.

More than 350 pro-GNA fighters have been killed and nearly 2,000 wounded in the battle, according to medical sources. IS casualties figures are unavailable.

Sirte itself has been emptied of its residents, apart from families of IS militants, according to the pro-GNA forces.

Pentagon spokesman Gordon Trowbridge in mid-August estimated that IS fighters in Sirte numbered fewer than 1,000.