Colonel Gaddafi's heavy armour is poised outside the town of Zawiya.Fierce fighting has rocked Libya's Zawiya, 50km (30 miles) west of Tripoli, as rebels repelled government efforts to retake the key city.
Pro-government forces were pushed out of the city centre in heavy fighting on Saturday morning, but regrouped for a fresh assault later in the day.Casualty figures were unclear, but heavy gunfire could be heard.
Meanwhile, rebels fighting Col Muammar Gaddafi have taken control of the port of Ras Lanuf to the east of Tripoli.
Observers say the overall balance of power is difficult to assess as the struggle for control over Libya continues.
In Tripoli, there is an air of growing confidence among regime loyalists as their control appears to be consolidated in Tripoli and other central areas.
But elsewhere, correspondents say rebel forces have an enormous determination to overthrow his regime.
In other developments:
- Hospital officials in opposition-held Benghazi say the death toll from a massive explosion at a weapons dump outside the city is at least 19, with the cause of the blast unknown
- Libyan state TV accuses the Netherlands of spying, following the capture on Sunday of a Dutch navy helicopter and its three-strong crew by government militias
- Rebels show reporters the wreckage of a downed warplane near Ras Lanuf in eastern Libya
- Thousands of migrant workers are on the move, trying to flee the violence, say officials at the UN's refugee agency. Most of those living in Benghazi have been evacuated, while about 10,000 others are heading for the Egyptian border
Reports from the coastal city said it had come under attack from both east and west from well-armed government forces in large numbers of tanks and armoured vehicles.
Heavy gunfire was heard in the central square as the rebels fought back using weapons they had captured earlier.
Pro-government tanks had circled the area in preparation for the fresh attack, shelling central areas of the city, where fires burned under a cloud of dense black smoke.Earlier, Zawiya resident and rebel supporter Mohammed told the BBC that pro-Gaddafi troops "came from east and west and they took up positions in high-rise buildings... and started shooting".
He said some tanks were captured and burnt near the town square, and that there were jubilant celebrations from the rebels as the pro-Gaddafi forces fled.
Another Zawiya resident, Hussein, said many civilians had been killed, including women and children - as up to 40 cars filled with soldiers attacked backed up by tanks and anti-aircraft guns.
"There are people dying everywhere. It is a disaster what is happening in Zawiya. We really need some help," Hussein told the BBC.
A doctor in the city said at least 30 people had died in Saturday's fighting.
UN quandary
In Ras Lanuf, an oil port east of Sirte - a key Gaddafi stronghold and his hometown - rebels have now taken control, according to a BBC correspondent who reached the town on Saturday morning.
Pro-Gaddafi forces who had been in the town were believed to have moved about 40km (25 miles) to the west.
They had withdrawn to Ras Lanuf two days ago after a battle a little further east in Brega.
