Savage fighting has erupted again in the strategic Libyan city of al-Zawiyah, raising the specter for a prolonged civil war between forced loyal to and opposed to Moammar Gaddafi.

Anti-government fighters repulsed efforts by Gaddafi supporters from retaking Zawiyah, which is about 30 miles west of the capitol, Tripoli.

After being driven out of the city center on Saturday morning, pro-government troops reorganized and made another assault in the afternoon.

Reportedly, Gaddafi tanks rolled into Zawiyah and shelled central parts of the city, creating a smoky inferno. A witness told BBC that government troops came from east and west and they took up positions in high-rise buildings... and started shooting.

He added, however, that rebel forces captured some of the tanks and again pushed out pro-Gaddafi soldiers.

Another Zawiyah witness told BBC that many civilians, including women and children, were killed here.

There are people dying everywhere. It is a disaster what is happening in Zawiyah. We really need some help, he said.

A witness told Britain’s Observer newspaper you must tell the world what is happening. Snipers are firing at anyone who moves.

Another witness stated The fighting has intensified and the tanks are shelling everything on their way. They have shelled houses. Now they are shelling a mosque where hundreds of people are hiding. We can't rescue anyone because the shelling is so heavy.

Gaddafi soldiers have established a heavy presence around the city.

Unconfirmed accounts spoke of heavy gunfire and significant casualties.

Simultaneously, rebel forces have seized control of key oil port Ras Lanuf –formerly a Gaddafi stronghold -- on the eastern side of Tripoli.

However, in Tripoli itself government loyalists appear to be enforcing their control – raising confusion about which side in the conflict has the advantage.