BIR AL-GHANAM, Libya, Aug 8 (Reuters) - Libyan rebels who captured the strategic town of Bir al-Ghanam, about 80 km (50 miles) south of Tripoli, were basking in glory on Monday when one saw a few vehicles approaching from the corner of his eye.
"They are coming," said the fighter as he and others ran to sand dunes and fired weapons at approaching Libyan army vehicles, forcing them to turn away.
It was a reminder that the rebels could face tough resistance when they try to advance to their next objective Zawiyah, a town 50 km (30 miles) west Tripoli.
Zawiyah has been the scene of two uprisings which were smashed by Libyan leader Muammar Gaddafi's security forces. A large contingent of the rebels who captured Bir al-Ghanam are from Zawiyah, so it holds special meaning for them.
As the takeover of Bir al-Ghanam suggests, getting there may not be possible without strong, sustained support from NATO, something rebels say they often lack.
Rebels said they opened fire with rockets from nearby ridges, then attacked government forces on foot and by pickup truck. Gaddafi's men hit back with rockets, killing five rebels, including a Libyan-American father and son who died holding each other in the battle lasting several hours, fighters said.
NATO airstrikes which pounded the small desert settlement may have been the deciding factor. They burnt three government tanks to a crisp, leaving a crater in the dirt beside the town's main road. A nearby house and factory were also pulverized, with twisted metal sticking out of concrete.
On the edge of town, a devastated military base looked like it had been covered by an ash cloud from a volcano.
A document authorising a soldier's leave was scattered in the destruction beside a book on praying by "The Great Leader"" Gaddafi and a poster proclaiming victory for the Libyan people.
Those scenes raised the confidence of rebels.
A group of them -- engineers, students and shopkeepers in their former lives -- sought refuge from the blistering sun under a tree. Lounging on some mattresses and ammunition and rocket crates, they bragged about their achievement and engaged in their favourite pastime of poking fun at Gaddafi, whom they call "the madman."
Taking Bir al-Ghanam broke weeks of stalemate during which rebels were unable to make big advances.
But many interviewed by Reuters said the next step -- advancing towards Zawiyah -- would be tough. To get there, they must grab a few small villages including one called Nasr, where they believe many hardcore pro-Gaddafi forces are stationed.
"There were a lot of African mercenaries in Bir al-Ghanam and we expect a lot more on the way to Zawiyah. We just finished burying some of them," said Tareq Gazal, 19. "They are the best fighters Gaddafi has. They are not afraid of death."
Gaddafi's government denies using mercenaries. It describes the rebels as armed gangs and al Qaeda sympathisers.
The rebels who seized Bir al Ghanam want payback. Gaddafi's men beat them in Zawiyah before and they believe taking it back would be a fatal blow to his 41-year rule.
The rebels say they have comrades in Zawiyah who went underground. The goal is to storm the city, team up with their allies, and eventually head for Tripoli.
"The problem is, the rebels in Zawiyah don't have many weapons," said Isa, who withheld his family name to protect relatives.
Editing by Douglas Hamilton and Angus MacSwan