ISLAMABAD, Pakistan -- Twice in recent weeks, the United States provided Pakistan with the specific locations of insurgent bomb-making factories, only to see the militants learn their cover had been blown and vacate the sites before military action could be taken, according to U.S. and Pakistani officials.
Overhead surveillance video and other information was given to Pakistani officials in mid-May, officials said, as part of a trust-building effort by the Obama administration after the killing of Osama bin Laden in a U.S. raid earlier in the month.
But Pakistani military units that arrived at the sites in the tribal areas of North and South Waziristan on June 4 found them abandoned.
U.S. officials say they do not know how the operation was compromised. But they are concerned that either the information was inadvertently leaked inside Pakistan or that insurgents were warned directly by Pakistan's Inter-Services Intelligence agency.
A senior Pakistani military official said Friday that the United States had also shared information about other sites, including weapons-storage facilities, that were similarly found empty. "There is a suspicion that perhaps there was a tipoff," the official said. "It's being looked into by our people, and certainly anybody involved will be taken to task."
In the past, Pakistan has strenuously denied allegations that its security services are colluding with insurgents.
The incidents are expected to feature prominently in conversations between Pakistani officials and CIA Director Leon Panetta, who arrived in Pakistan on Friday.
The U.S. argument, one official said, will be: "We are willing to share, but you have to prove you will act. Some of your people are no longer fully under your control."
U.S. officials said Panetta would also carry a more positive message, reiterating that the United States wants to rebuild a trusting, constructive relationship with Pakistan.
Immediately after bin Laden's death, some administration officials and lawmakers argued that the al-Qaida leader's presence in a suburban Pakistani compound was reason enough to withhold U.S. assistance from Pakistan.
But the prevailing view has been that the two countries need each other despite their problems.