* Rebels use mountains to thwart Gaddafi advance
* Pro-Gaddafi forces shelling mountain-top towns
* Fighting intensified in past few days
By Matt Robinson
KABAW, Libya, May 12 (Reuters) - Colonel Tarek Zanbou stood high above the desert plains where Libya meets Tunisia, and explained how his rebels happen to hold the Western Mountains. He was brief.
“The geography is with us,” he said, in English honed at Durham University in the northeast of England.
With their planes grounded by NATO, it is hard to imagine how forces loyal to Muammar Gaddafi can expect to retake the chain of hardscrabble towns that sit atop the Western Mountains, on a vast, bleak plateau of sand and scrubland.
Ill-equipped and poorly-trained, the rebels hold a single mountain-top road that runs about 200 km (125 miles) from the Tunisian border to just beyond the town of Zintan, some 150 km short of the capital, Tripoli.
Crucially, they seized the border crossing last month, opening a vital artery for food, fuel and medical supplies.
Their families had already fled across the frontier, to live in Tunisian homes or in camps under the blistering North African sun.
Only the men remain, most of them armed and waiting for Gaddafi to fall.
“Now, we are just defending,” said 43-year-old Zanbou, who said he served as an intelligence officer in Gaddafi’s army based in Tripoli. “If we get weapons, we can push them (pro-Gaddafi forces) to Tripoli. But now we are in a defensive situation.”
The sound of rebel gunfire ricocheted between the mountains. “We are sending them a message that we have everything,” he said, “when in reality we have nothing.”
With good reason, Zanbou’s ambitions are modest. In Kabaw, some 230 km southwest of Tripoli, Zanbou’s band of men is hardly the most formidable.
At training on Wednesday, after chanting “We’re coming, Muammar!” most struggled to strip and reassemble their old, rattling Kalashnikov rifles.
In Zintan, they have a few tanks, but lack the expertise to use them effectively, while some of the anti-aircraft guns mounted on pick-ups appear to be decades old.
They lost six men on Wednesday, including a 17-year-old, when an attempt to block a road used by loyalist forces turned into a shooting match with villagers seen as supporting Gaddafi.
The fight in the Western Mountains has been overlooked by all sides in favour of the eastern front centred on Benghazi, and the besieged port city of Misrata to the east of Tripoli.
Strategically, both appear to pose a more direct threat to Gaddafi’s hold on the capital, though the two-month-old conflict, after see-sawing repeatedly, has now settled into a violent stalemate.
In the Western Mountains, the loyalist army has limited itself to lobbing artillery at the mountain tops from positions in the plains below, and an ill-fated operation to retake the border crossing that was quickly reversed.
The shelling has hit residential areas, and in Zintan an unexploded rocket is lodged in the grounds of the hospital. Like the rebels, the loyalists are holding the line.
NATO planes, meanwhile, enforce a no-fly zone which prevents loyalist forces bombing the rebels from the air, and are pounding government weapons depots near Zintan. But rebels say NATO is doing little else to help.
Fighting, however, has picked up in recent weeks around Zintan, which is surrounded on three sides by pro-Gaddafi forces and frequently comes under artillery fire, rebels say.
Around 12 rebels were killed last weekend in fighting with loyalist troops. “My impression is it’s on the increase,” said Doctor Morten Rostrup of Medecins Sans Frontieres at Zintan hospital.
“The rebels appear to be trying to push back the loyalist forces so the town is no longer within range of their artillery. But if they are to keep supplying the front, control of the border crossing down in the plains will be key.”
“If he (Gaddafi) controls that border, he kills the people,” said Zanbou, “because everything is coming through there.” Zanbou is a member of the Berber ethnic minority which populates much of the Western Mountains and has long complained of discrimination under Gaddafi.
They were quick to raise the rebel flag when rebellion erupted in February seeking an end to Gaddafi’s 41-year-rule, and the men of Kabaw drove his army from its cliff-top position outside the town.
Now, the rebel flag flies from car windows and homes. A cultural centre dedicated to Gaddafi has been trashed and torched, and a rug bearing his face serves as a doormat at Kabaw’s library-turned-military HQ.
On the road, cars slalom around mounds of earth, tyres and rocks to approach checkpoints manned by armed men slouched in office chairs, seemingly safe in the knowledge they hold the high ground.
“No one has any idea how to fight, but God is with us,” said an elderly man, who declined to be named, at a checkpoint near the entrance to Zintan.
To 25-year-old engineer Murad Maghlouf, the reason is far simpler: “We know the mountain.” (Editing by Ralph Boulton)