Libya conflict: Gaddafi fights back as rebels advance
Pro-Gaddafi forces in Libya have been fighting back at the oil port of Brega as rebels consolidate their hold on key cities either side of Tripoli.
Rebels forces who took control of Brega on Friday fell back from the eastern town's industrial zone under heavy bombardment, a rebel spokesman said.
But the rebels control Zlitan, 160km (100 miles) east of Tripoli, and Zawiya, 30km to the west.
Explosions and heavy gunfire were heard in Tripoli late on Saturday.
The BBC's Matthew Price in Tripoli says it sounded like exchanges of gunfire, rather than people firing into the air.
Our correspondent says that the momentum is clearly against Col Gaddafi and his supporters, both militarily and politically.
Either his forces have pulled back in places like Zlitan in order to prepare for a fresh offensive or, after months of Nato air strikes, elements of the army may simply be too weak to fight on, our correspondent adds.
A rebel military spokesman, Col Ahmed Bani, confirmed that rebel forces had fallen back in Brega.
Brega, home to Libya's second-largest hydrocarbon complex and the place where the country's main oil fields feed into for refining, has repeatedly changed hands during the six-month-old conflict.
"Yesterday, the industrial zone was under our complete control, but the truth is that today the situation has changed due to heavy artillery shelling," Col Bani said.
"We withdrew to the eastern part of the industrial zone."
After visiting Zlitan, the BBC's Orla Guerin said the rebels appeared to have a firm grip on the town, controlling the centre and manning checkpoints.
However, small-arms and mortar fire could still be heard, and rebels told the BBC that beyond a strategic bridge in the centre, there was still a risk of attack.
The BBC's Rupert Wingfield-Hayes in Zawiya said the rebels appeared to have succeeded in pushing Col Gaddafi's forces out of the city.
He said the bodies of sub-Saharan Africans could be seen on the streets, amid claims by the rebels that many of those fighting for Col Gaddafi were foreign mercenaries.
Rebel forces have also moved towards Tripoli from the south.
Nato, enforcing a UN-mandated no-fly zone to protect civilians since March, controls sea access to Tripoli.
Late on Friday, Col Gaddafi's Information Minister, Moussa Ibrahim, continued to insist government troops had the upper hand in both Zlitan and Zawiya.
Meanwhile, reports suggest fresh senior figures in the Gaddafi camp may have defected:
- Abdel Salam Jalloud, who helped Col Gaddafi come to power in 1969 but fell out with him in the 1990s, is believed to be making his way to Europe from neighbouring Tunisia
- Libyan Oil Minister Omran Abukraa failed to return to Libya on Thursday after a visit to Italy and went to Tunisia instead, Tunisian sources said
Libya's conflict broke out in February, inspired by uprisings in Tunisia and Egypt which toppled the presidents of those countries.
Rebels in the east rapidly consolidated their gains, but a stalemate developed in the west as rebels there faced overwhelming military force.
The fighting has stranded thousands of migrant workers - many of them Egyptians - in Tripoli.
The International Organisation for Migration (IOM) said it was planning to evacuate them in the coming days.
Since the conflict in Libya began, an estimated 600,000 migrant workers have fled the country, many with the help of the IOM, but many remain.