The New York Times reports:

As rebel forces in Libya converged on Tripoli on Sunday, American and NATO officials cited an intensification of American aerial surveillance in and around the capital city as a major factor in helping to tilt the balance after months of steady erosion of Col. Muammar el-Qaddafi’s military.

The officials also said that coordination between NATO and the rebels, and among the loosely organized rebel groups themselves, had become more sophisticated and lethal in recent weeks, even though NATO’s mandate has been merely to protect civilians, not to take sides in the conflict.

NATO’s targeting grew increasingly precise, one senior NATO diplomat said, as the United States established around-the-clock surveillance over the dwindling areas that Libyan military forces still controlled, using armed Predator drones to detect, track and occasionally fire at those forces.

At the same time, Britain, France and other nations deployed special forces on the ground inside Libya to help train and arm the rebels, the diplomat and another official said.

The Guardian reports:

While most of the world’s attention had focused throughout the conflict on the continual attempts by Benghazi-based rebels to secure the oil town of Brega, and simultaneous efforts to break out of the opposition enclave of Misrata, a pivotal breakthrough took place in what had hitherto been considered a sideshow in the Libyan war – the western mountains.

The Nafusa highlands, as the range is called, stretches south-west of Tripoli and forms a natural barrier between the capital and Libya’s interior. Its Berber inhabitants, the Amazigh community, had turned against Gaddafi early on but had been bottled up in their home villages since the spring by government forces. Every attempt to break through government lines into the coastal plains to the north had been rebuffed.

During the spring and early summer, however, Amazigh fighters were joined by dissidents streaming out of Tripoli and the oil refining port of Zawiya, fleeing Gaddafi’s brutal suppression of the uprising there. In the Nafusa highlands a more effective fighting force was fused from these disparate elements with the help of Nato trainers and French air-drops of arms and equipment.

By early August, these fighters began to push out from their bases. They moved village by village at first, and the offensive was little noticed outside the region. But it quickly grew and by the beginning of last week the mountain rebels had arrived at Gharyan, a heavily fortified city 60 miles south of Tripoli, and were beginning to infiltrate Zawiya as well.

Previous attempts to take Zawiya had been pushed back by Gaddafi forces, exposing the over-ambition and tenuous supply lines of the rebel attacks. This time, the rebels took central Zawiya and stayed. By Friday they had seized the coastal oil refinery. They had not only cut the road between Tripoli and the Tunisian border, along which the regime imported most of its food and basic supplies, but had turned off the last trickle of refined fuel going into the capital. “The fall of Zawiya was the pivotal moment in hindsight. It not only had practical effects, severing road links and so on, it was also an enormous psychological blow [for Gaddafi forces],” said Shashank Joshi, a military analyst at the Royal United Services Institute in London. “The death of Younes had not been as bleak for the rebels as we had thought. The battle had already shifted its centre of gravity to the Nafusa range. The rebels adapted and learned. They realised that their reckless advances without consolidating their positions weren’t working. They began to move methodically, and took orders, waiting for Nato soften up the defences before moving in.”

Evidence of greater discipline and better co-ordination with Nato air strikes was apparent on every front. Rebel commanders were told not to stray over “red lines” marked out by Nato liaison officers as “free fire zones”. Rebel forces had attempted to mark their vehicles to avoid friendly fire from alliance jets, painting them black or painting a white “N” on them, but the markings were not universally applied and quickly copied by government forces.

When Misrata-based forces finally broke through government lines at Zlitan on Friday, however, the bonnets of their vehicles were clearly draped with red and yellow flags, provided by Nato and kept under wraps until the offensive.

Special forces played a key role in that close relationship, though UK government officials declined to comment on whether serving SAS personnel were involved, including acting as forward air controllers – directing pilots to targets on the ground. Reports that France deployed special forces to Libya have also not been convincingly denied. In addition, Qatari and Jordanian special forces also played a role, the Guardian has been told, while Qatar is believed to have paid for former SAS and western employees of private security companies.

Radar, cameras and listening devices on Nato planes, including RAF Sentry and Sentinel surveillance aircraft, based in Sicily and Cyprus, and US Predator drones, could identify clear military targets such as tanks, armoured vehicles, as well as known command and control centres.