Fighting raged on Sunday in Zawiyah after Libyan insurgents launched an offensive to recapture the western port they lost to Muammar Gaddafi’s forces in March, a rebel source said.
The fighting, which follows more than two months of relative calm in the city of 250,000 people, began on Saturday, the source told AFP in the rebel capital Benghazi, adding that the fighting had caused "very many casualties."
"Fighting that started yesterday between battalions loyal to Gaddafi and rebels from Zawiyah is continuing and causing very many casualties," the rebel leader said.
Loyalist forces blocked the road to the Tunisian border to "prevent the flow of refugees" from the town, located around 50 kilometres (31 miles) west of Tripoli, he added.
It was not immediately possible to confirm the reports independently.
Government forces retook control of Zawiyah in March after bloody battles with the rebels, who launched a popular uprising against Gaddafi’s four-decade hardline rule mid-February.