Pakistan President Pervez Musharraf has struck a deal with the US not to capture Osama bin Laden, fearing this could lead to unrest in Pakistan, according to a special investigation by The Guardian.

The paper reported on Saturday that bin Laden was being protected by three elaborate security rings manned by tribesmen stretching 192 km in diameter in northern Pakistan.

The paper's information is based on comments made by Mansoor Ijaz, an American of Pakistan origin who, the papers said, knows Al-Qaida better than most people and has had close contacts in Pakistan's intelligence agencies.

Ijaz believed an agreement was reached between Musharraf and US authorities shortly after bin Laden's flight from his stronghold Tora Bora in Afghanistan in December 2001.

The Pakistanis feared that to capture or kill bin Laden so soon after a deeply unpopular war in Afghanistan would incite civil unrest in Pakistan and trigger a spate of revenge Al Qaida attacks on Western targets across the world.

"There was a judgment made that it would be more destabilising in the longer term. There would still be the ability to get him at a later date when it was more appropriate", Ijaz told The Guardian.

The Americans, according to Ijaz, accepted the argument, not least because of the shift in focus to the impending war in Iraq.

So the months that followed were centred on taking down not bin Laden but the "retaliation infrastructure" of Al-Qaida.

It meant that Musharraf frequently put out conflicting accounts of the status of bin Laden, while the US administration barely mentioned his name.

In January last year Musharraf said he believed bin Laden was probably dead. A year later he said he was alive and moving either in Afghanistan or perhaps in the Pakistani tribal areas.

"Yet Western diplomats say they believe the Pakistani authorities are committed to the hunt for bin Laden, although they admit that frequently the official accounts of the timing and location of successful arrests do not square with reality," the report stated.

"Pakistan must now end the charade and get bin Laden... With so much of the retaliation infrastructure gone or unsustainable, bin Laden's martyrdom does not pose nearly the threat it did a year ago," Ijaz told the paper.

According to Ijaz, bin Laden is hiding in the "northern tribal areas", part of the long belt of seven deeply conservative tribal agencies which stretch down the length of the mountain ranges that mark Pakistan's winding border with Afghanistan.

The paper said that Ijaz, who recently visited Pakistan, believed that bin Laden was protected by an elaborate security cordon of three concentric circles, in which he is guarded first by a ring of tribesmen, whose duty is to report any approach by Pakistani troops or US Special Forces.

Inside them is a tighter ring, around 19 km in diameter, made up of tribal elders who would warn if the outer ring were breached.

At the centre of the circles is bin Laden himself, protected by one or two of his closest relatives and advisers.

Bin Laden has reportedly agreed with the elders that he will use no electronic communications but handwritten notes, and will move only at night and between specified places within a limited radius.

Pakistani Interior Minister Faisal Saleh Hayat told the daily: "We have been getting reports of his presence across the border inside Afghanistan and along the border area also.

"Not all reports have been credible at times. If others were credible, we would certainly have been able to get near to him but certainly that has not been the position so far."

Talat Masood, a retired Pakistani general and security analyst said: "I think the Americans find their reliance on the Pakistanis now is increasing."