Libya's rebels have traded heavy artillery fire with Muammar Gaddafi's forces near the western city of Zlitan as they tried to take government-held territory east of the capital Tripoli.

The city, 160 km (100 miles) from Tripoli, is the next major town on the Mediterranean coastal road to the capital from the rebel stronghold of Misrata. Capturing it would greatly advance the rebels' strategy of cutting off the capital from all sides.A Reuters team in Dafniya, on the outskirts of Misrata, said rebels fired artillery and rocket launchers. Rebels said they aimed to hit Libyan tanks and munitions in Naimah, near Zlitan, but inexperience and indiscipline has plagued their campaign.

"We had a strategy to finish everything today, but some of the fighters think it's a game. They shot when they weren't supposed to shoot," a rebel unit commander called Mohammed Ali told Reuters, after taking cover from a mortar barrage.NATO planes resumed bombardments of Tripoli on Friday with six explosions sending columns of black smoke into the sky.Rebel advances toward Tripoli have been slow, and weeks of NATO strikes pounding Gaddafi's compound and other targets have failed to bring an end to his 41-year-old rule.Rebels are fighting on two other fronts: in the east around the oil town of Brega and in the Western Mountains southwest of Tripoli. They have made important gains in the past few weeks, but remain far from seizing their ultimate prize.