WASHINGTON, Aug 22: The rapid weekend advance of Libyan rebel troops into Tripoli was planned two weeks ago by British, French and Qatari special forces on the ground, The Washington Post reported on Monday.

The United States provided additional intelligence on the positions of Libyan government forces, Nato and US military and intelligence officials told the Post.

The strategy included coordinated rebel attacks on three critical areas: the oil port of Brega, the refinery city of Zawiyah and the strategic southern approach to Tripoli at Gharyan.

The objective was to compel Libyan government forces to move into Tripoli and thus provide clear targets for Nato airstrikes. It would also clear the roads for the rebel advance.

Nato aircraft hit 22 targets in and around Tripoli on Saturday as rebels launched their offensive.

Meanwhile, the United States had begun to provide its allies with expanded imagery from satellites and armed drones on the locations and capabilities of government forces.

CIA operatives inside the country also shared with the rebels intercepted communications within the government, which provided a deeper understanding of just how badly Col Qadhafi's command structure had crumbled.

The Nato allies and “particularly the Qataris” on the ground were “working very closely” with the rebels' military and political command “to help them think this one through and also provide them with the capabilities”, the Post reported.

But the newspaper observed that the speed of the collapse had taken aback even those who had planned it.

“For the most part the Libyan regime forces seem to have just not engaged,” a US intelligence official said. “Somehow this seems to have literally passed them by.”

Even as rebels seized control of large areas in Tripoli, US military officials said it was unclear how long the fighting in the capital would continue.

US officials told the post that the CIA and the US National Security Agency were going to expand their support to the rebels, providing them new information about Col Qadhafi's whereabouts and on his remaining military strength.