"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," The Washington Post reported, quoting US and Pakistani officials.
Overhead surveillance video and other information was given to Pakistani officials in mid-May, the officials said, as part of a trust-building effort by the Obama administration after the killing of Osama bin Laden in a US raid in Abbottabad.
The video of the two bomb-making factories was handed over to Pakistani army chief Gen Ashfaq Parvez Kayani and ISI head Lt Gen Ahmed Shuja Pasha during a visit last month by Marc Grossman, the Obama administration''s special representative to Afghanistan and Pakistan, and CIA Deputy Director Michael J Morell, the daily said.
But, Pakistani military units that arrived at the sites in the tribal areas of North and South Waziristan on June 4 found them abandoned, the report said.
According to the Post, US 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 insurgents were warned directly by Pakistan's Inter-Services Intelligence directorate, or ISI," it said.