Rebels cheered the defection of a Libyan minister as a sign that Muammar Gaddafi’s rule was crumbling, but US officials warned he was far from beaten.
Libyan rebels pulled out of the oil town of Ras Lanuf on Wednesday under heavy bombardment from Muammar Gaddafi’s forces.
Muammar Gaddafi’s troops reversed the westward charge of Libyan rebels as world powers met in London on Tuesday to plot the country’s future.
Western warplanes bombed Muammar Gaddafi’s armour in eastern Libya on Friday to try to break a battlefield stalemate and help rebels take Ajdabiyah.
Nato said it would enforce a Libya no-fly zone but stopped short of taking full command of UN-backed military operations.
Western warplanes hit Libya for a fifth night on Thursday, but have so far failed to stop Muammar Gaddafi’s tanks shelling rebel-held towns.
Western warplanes silenced Muammar Gaddafi’s artillery and tanks besieging the rebel-held town of Misrata on Wednesday.
Western powers pounding Libya’s defences will wind up in the dustbin of history, said leader Muammar Gaddafi as his troops held back rebel advances.
Anti-aircraft fire rang out across Tripoli for a third night on Monday, but air attacks on Libya are likely to slow.
Western powers launched a second wave of air strikes on Libya early on Monday.