It wants to know whether any Pakistani official had links with Osama

Pakistani officials say the Obama administration has demanded the identities of some of their top intelligence operatives as the United States tries to determine whether any of them had contact with al-Qaeda chief Osama bin Laden or his agents in the years before the raid that led to his death early Monday in Pakistan.

The officials provided new details of a tense discussion between Pakistani officials and a U.S. envoy who travelled to Pakistan on Monday, as well as the growing suspicion among U.S. intelligence and diplomatic officials that someone in Pakistan's secret intelligence agency knew of bin Laden's location, and helped shield him.

Obama administration officials have stopped short of accusing the Pakistani government either privately or publicly of complicity in the hiding of bin Laden in the years after the September 11 attacks on the World Trade Center and the Pentagon. One senior administration official privately acknowledged that the administration sees its relationship with Pakistan as too crucial to risk a wholesale break, even if it turns out that past or present Pakistani intelligence officials did know about bin Laden's whereabouts.

Still, this official and others expressed deep frustration with Pakistani military and intelligence officials for their refusal over the years to identify members of the Inter-Services Intelligence Directorate believed to have close ties to bin Laden. In particular, on Monday and in the past U.S. officials have demanded information on what is known as the ISI's S directorate, which has worked closely with militants since the days of the fight against the Soviet army in Afghanistan.

“It is hard to believe that Kayani and Pasha actually knew that bin Laden was there,” a senior administration official said, referring to Pakistan's Army chief, General Ashfaq Parvez Kayani, and the ISI director-general, Lt. Gen. Ahmad Shuja Pasha. But, the official added, speaking on the condition of anonymity because of the diplomatic sensitivity of the issue, “there are degrees of knowing, and it wouldn't surprise me if we find out that someone close to Lt. Gen. Pasha knew.”

Already, Pakistani news outlets have been speculating that Lt. Gen. Pasha, one of the most powerful figures in Pakistan, may step down as a consequence of the bin Laden operation.

Increasing tensions

The increasing tensions between the United States and Pakistan, whose proximity to Afghanistan makes it almost a necessary ally in the American and allied war there, came as the al-Qaeda itself acknowledged on Friday the death of its leader. The group did so while vowing revenge on the United States and its allies.

Pakistani investigators involved in piecing together bin Laden's life during the past nine years said this week that he had been living in Pakistan's urban centres longer than previously believed.

Two Pakistani officials with knowledge of the continuing Pakistani investigation say bin Laden's Yemeni wife, one of three wives now in Pakistani custody since the Monday raid, told investigators that before moving in 2005 to the mansion in Abbottabad where he was killed, bin Laden had lived with his family for nearly two and a half years in a small village, Chak Shah Mohammad, a little more than a mile southeast of Haripur, on the main Abbottabad highway. In retrospect, one of the officials said, this means that bin Laden left Pakistan's rugged tribal region sometime in 2003 and had been living in the northern urban regions since then. U.S. and Pakistani officials had thought for years that ever since bin Laden disappeared from Tora Bora in Afghanistan, he had been hiding in the tribal regions straddling the Afghanistan-Pakistan border.

A former Pakistani official noted that Abbottabad, the site of the Pakistani equivalent of the West Point military academy, is crawling with security guards and military officials who established a secure cordon around the town, raising questions of how the officials could not know there was a suspicious compound in their midst.

“If he was there since 2005, that is too long a time for local police and intelligence not to know,” said Hassan Abbas, a former Pakistani official now teaching at Columbia University.

Mr. Abbas said there was a tight net of security surrounding Abbottabad because Pakistani officials were concerned about terrorist attacks on sensitive military installations in the area.

Art Keller, a former officer of the Central Intelligence Agency who worked on the hunt for bin Laden from a compound in the Waziristan region of Pakistan in 2006, said the al-Qaeda founder's choice of the garrison town of Abbottabad as a refuge in 2005 raised serious questions. Bin Laden certainly knew of the concentration of military institutions, officers and retirees in the town including some from the ISI's S directorate, Mr. Keller said. And because the military has also been a target of militant attacks in recent years, the town has a higher level of security awareness, checkpoints and street surveillance than others.

If bin Laden wanted to relocate in a populated area of Pakistan to avoid missiles fired from U.S. drones, Mr. Keller said, he had many choices. So Mr. Keller questioned why bin Laden would live in Abbottabad, unless he had some assurance of protection or patronage from military or intelligence officers. “At best, it was wilful blindness on the part of the ISI,” Mr. Keller said. “Wilful blindness is a survival mechanism in Pakistan.”

The trove of information taken by the commandos from the compound occupied by bin Laden may answer some questions, and perhaps even solve the puzzle of where he has been in recent years.

A senior law enforcement official said on Friday that the FBI and the CIA had rapidly assembled small armies of analysts, technical experts and translators to pore over about 100 thumb drives, DVDs and computer disks, along with 10 computer hard drives, five computers and assorted cellphones. Analysts are also sifting through piles of paper documents in the house, many of which are in Arabic and other languages that need to be translated.

In Washington and New York alone, several hundred analysts, technical experts and other specialists are working round-the-clock to review the trove of information. “It's all hands on deck,” said the official, who spoke on the condition of anonymity because of the continuing investigation.

Technical specialists are recovering phone numbers from several cellphones seized at the compound. The experts need to distinguish foreign telephone contacts from any numbers in the United States, which undergo a separate legal review, the official said.

“We are also looking through notes, letters, emails and other communications,” the official said. “We are looking at who owns the emails and what linkages there are to those people.” The official said the initial analysis would involve searching for information about specific threats or plots, or potential terrorists sent to the United States or Europe, and that the FBI was pursuing a small number of leads from the information reviewed so far. — New York Times News Service

(Helene Cooper reported from Washington, and Ismail Khan from Peshawar, Pakistan. Eric Schmitt, Scott Shane and Mark Mazzetti contributed reporting from Washington.)