Heavy fighting has erupted on the outskirts of Zawiya in western Libya as Qaddafi's regime was forced to employ heavy artillery to fend off a rebel assault on the bridge leading into the town from the south, foreing news agencies report.

Zawiyah witnessed the strongest uprising in the west of Libya against the regime in February, but Qaddafi forces crushed the uprising in a brutal assault that destroyed the town's main bridge.
A key strategic prize for both sides as it straddles the main road to the Tunisia border – Zawiya is the regime's main supply line. The highway from the capital to the Tunisian border was blocked there.
The city also is home to the only functioning oil refinery in Qaddafi regime's control, though it also has a desperate grip on the damaged facilities in the key town of Brega.
The fighting around Zawiya comes as rebels also advanced through the Nafusa mountains, having entered the town of Gharyan before being stopped dead and forced to dig in by Qaddafi troops.
The recapture of Zawiya, which has become a potent symbol of the Libyan uprising, would be hugely significant. Half an hour's drive from the capital, Tripoli, and located on the western approach to the capital, it would threaten a key supply line for pro-Qaddafi forces. However, there are a number of significant military bases near the town.
A victory there would be an invaluable morale boost for the now-contentious rebels, whose top miliary commander Abdel Fatah Younes was assassinated under suspicious circumstances leading to the sacking of the rebel political eschelon's executive council.
Michael Georgy of Reuters, reported being told of a heavy battle, with pro-Qaddafi forces using anti-tank guns in which rebel fighters pushed government troops back about 7 km from their previous positions, fixing a frontline about 5 km north of the village of Bir Shuaib.
AP told a similar story, quoting rebel commander Fathi el-Ayeb saying his fighters were about 15 km from Zawiya. Ayeb added that rebel scouts who had returned from Zawiya claimed that local people there were waiting for the rebels to reach the city's outskirts to join their fight against Qaddafi. 
"They are waiting for the rebels to come and they will join them," he said
Meanwhile, a captured Qaddafi general says NATO underestimated the support Qaddafi enjoys in the Tripoli region.
Reports said a rebel force of about 200 fighters has reached a bridge on the southwestern outskirts of the city, which is located around 30 miles west of Tripoli.
Hundreds of residents rushed into the streets, greeting rebels with chants of "Allahu akbar," or "God is great."
Despite significant advances by the rebels in recent days, the regime appeared to have just lightly armed troops in shops and garages in the town yesterday afternoon. Sandbags had been erected at the town's junctions in preparation for street-to-street fighting.
The regime spokesman, Moussa Ibrahim, said the onslaught had been rebuffed.
He said fewer than 100 rebels entered the city from the south and they tried to join up with 50 rebels within the city, who had been "dealt with".
"A very small group of rebels tried to move into the south of Zawiyah but they were stopped easily because of our armed forces," he said.