America is stepping up its hunt for Osama bin Laden by dispatching additional CIA operatives and paramilitary officers to Pakistan to kill or capture the al-Qa'eda leader.
US officials said that the mission is intended to intensify the pressure on the terrorist leader, who turns 50 tomorrow, and perhaps force him into making a mistake. He is widely believed to be hiding in the region bordering Afghanistan.
Satellite photographs and details of communications intercepts were given to President Musharraf of Pakistan last week by Stephen Kappes, deputy director of the CIA, as part of a strategy to persuade him to give US intelligence agencies more assistance.
Mr Kappes, a Middle East specialist who has served in Pakistan, travelled to Islamabad to brief Gen Musharraf along with Vice President Dick Cheney. His detailed presentation showed evidence of al-Qa'eda building its strength on Pakistani soil.
"Reports that the trail has gone stone cold are not correct," an American official said afterwards. "We are very much increasing our efforts there."
Mr Kappes also met members of Pakistan's Inter-Services Intelligence agency (ISI) and operatives from the CIA's Islamabad station to discuss co-ordinating efforts to track bin Laden.
The decision to send such a senior intelligence officer to brief Mr Musharraf is an indication of the Bush administration's increasing concern about the borderlands between Pakistan and Afghanistan.
Last week, Adml Mike McConnell, the new US Director of National Intelligence, told a Senate committee that bin Laden, who turns 50 tomorrow, is in Pakistan and actively re-establishing al-Qa'eda training camps there.
It was the most specific information about bin Laden given by a US official for several years and prompted speculation that surveillance photographs of the al-Qa'eda leader or his deputy might have been obtained.
Adml McConnell said of the Pakistani tribal area that "to the best of our knowledge the senior leadership, Number One and Number Two, are there, and they are attempting to re-establish and rebuild and to establish training camps."
Intelligence officials have indicated that bin Laden has previously chosen March to switch locations, moving to hiding places in the mountains once the snow cover begins to melt. He is likely to be at his most vulnerable when on the move.
Adml McConnell said he would focus with "great intensity" on al-Qa'eda in Pakistan. "There are a number of plans and activities that have been shut down or disrupted. And the intent on our part is to do that more and better, and hopefully at some point either killing or capturing the senior leadership."