Rebels fought forces loyal to Libyan leader Muammar Gaddafi for a second day in the town of Zawiyah on Sunday, bringing the revolt against his rule to within a few kilometres (miles) of the capital.
A rebel spokesman in the town said 13 rebel fighters and civilians were killed in fighting there on Saturday, and the main road to neighbouring Tunisia -- a supply line that has kept the country running despite sanctions -- was shut.
Zawiyah was the scene of battles in February and March. Gaddafi's forces snuffed out that rebellion and used bulldozers to flatten the town's central mosque. But on Saturday, Reuters reporters nearby said the fighting had broken out again.
"The situation is bad, very bad," a rebel spokesman, who gave his name as Ibrahim, told Reuters on Sunday by telephone from Zawiyah, which is about 50 km (30 miles) west of Tripoli.
"Fierce fighting is taking place now. The (pro-Gaddafi) brigades have been receiving reinforcements ... There are many snipers on rooftops of buildings and mosques. They are the main threat to the residents," he said.
"The coastal road linking Tripoli to Tunisia is closed. The brigades are in control of the eastern side of the road while the revolutionaries control the western side.
"There were 13 martyrs, including a 7-year old boy, from fighting yesterday."
Accounts from Zawiyah could not be independently verified because reporters were not able to reach the town itself.
Officials in Tripoli say there is no serious fighting in Zawiyah, just small groups of fighters who have gone there from rebel-held areas to "make trouble".
BALANCE OF FORCES
The defeat of Zawiyah's previous rebellion marked the restoration of Gaddafi's control over western Libya after the first, chaotic few weeks when people across the Arab North African country rose up against his four-decade-old rule.
Three months later, the balance of forces appears to have shifted, with Gaddafi under pressure from sanctions, defections from his entourage and NATO air strikes that have been pounding his Bab al-Aziziyah compound in the capital.
Western governments say they believe that it is only a matter of time before his rule collapses, while rebels are gradually expanding the areas they control around Misrata, a city east of Tripoli, and in the Western mountains region.
A rebel spokesman in Zintan, part of the rebel-held mountain range south-west of Tripoli, said pro-Gaddafi forces were mounting a heavy artillery bombardment."
"They (pro-Gaddafi forces) launched a vast attack at 07:00 this morning, using mortars and Grad rockets," the spokesman, called Abdulrahman, told Reuters from Zintan.
"The shelling is still going on ... The revolutionaries are trying to defend the town," he said.