Fighters of the Libyan Central Shield say they have captured Tripoli's battered international airport after ten days of clashes with nationalist armed groups.

A statement shown on screen on An-Nabaa television, regarded as close to the Islamist fighters, said: "Fajr Libya announces that it totally controls Tripoli international airport", referring to the Libya Dawn brigade that is fighting under the umbrella of the Libyan Central Shield.

The airport changing hands is a major defeat for the nationalist fighters from Zintan west of Tripoli who have held the airport since the fall of Muammar Gaddafi in 2011.

Earlier on Saturday, leaders of the Libyan Central Shield, partly comprising men from Misrata, east of Tripoli, said their forces were advancing on the airport, having taken a bridge and a military base.

The strategic site 30km south of the Libyan capital, has been shut since July 13 amid skirmishes between Libyan Central Shield fighters and the Zintan force which is allied with renegade general Khalifa Haftar.

The claim of control on Saturday followed a setback the previous night when an unidentified jet raided the positions of the Libya Dawn, killing at least 10 fighters, a spokesman for the militia said.

Libyan Central Shield spokesman Mohamed al-Ghariani said he could not identify the warplane that carried out the raid, just as two aircraft which bombarded Islamist positions on Monday night remain unidentified.

Neither the targeted fighters nor the Libyan government, lacking real power and holed up in Tobruk 1,600km east of Tripoli, have been able to shed light on the provenance of the two planes in Monday's raid.

The latest deadly strike targeted an army base to the south of Tripoli and a nearby warehouse, Ghariani said on An-Nabaa television.