Bin Laden hiding in mountains - report

US military chiefs reportedly believe Osama bin Laden is hiding in the mountains between Afghanistan and Pakistan after escaping the assault on the cave complex of Tora Bora.

But up to a third of bin Laden's most senior lieutenants have been killed in the war in Afghanistan, according to a report in an American newspaper.

Intelligence experts say they are no closer to capturing bin Laden as they do not have specific information that could be used to launch an attack on his hide-out.

A senior American official said that capturing or killing the al-Qaida leader was "a long-term proposition".

The search for bin Laden has been hampered by a string of bad intelligence reports, including the deliberate giving of false information about his whereabouts.

But intelligence officials now believe they have pinned down the area where bin Laden is hiding to the mountainous Afghan-Pakistani border.

"We are quite certain he is alive and we think he is somewhere between Afghanistan and Pakistan," said the official. "It may be that he moves back and forth between the two."

The area is the same one in which US troops have been concentrating their search since last November but it is different from the area of Kashmir where the SAS are reported to be hunting bin Laden.

US officials also revealed that they now believe up to a third of bin Laden's entourage have been killed.

They are confident 20 to 25 senior al-Qaida members have been killed in the fighting in Afghanistan, and in particular during the attacks on the Tora Bora complex.