Rebels have been engaged in fierce firefights with government forces in mountain plains about 80km (50 miles) south-west of Tripoli.

A BBC correspondent who was with the rebels was told by a volunteer medic two of them had died in the battle.

The rebels said government forces suffered far greater casualties, although that cannot be confirmed.

Meanwhile, Col Muammar Gaddafi has agreed to stay out of talks on ending the conflict, African leaders said.

In a communique after talks on Sunday in South Africa, the African Union panel on Libya said it "welcomes Colonel Gaddafi's acceptance of not being part of the negotiations process". The statement did not elaborate.