C.I.A. director Leon E. Panetta took an unannounced trip to Pakistan on Friday to confront the leader of the Pakistani intelligence service, Lt. Gen. Ahmed Shuja Pasha, over accusations that Pakistani government had tipped of militants staging an attack in Afghanistan, the New York Times reports

This was the evidence of collusion presented: the C.I.A. had alerted the Pakistanis about the existence of two bomb-making facilities several weeks ago and asked them to raid the locations. One of the locations, according to the Telegraph, was operated by al-Qaeda. But when the Pakistani Army showed up, the militants were gone, which made the C.I.A. suspicious that the militants had warning from someone on the Pakistani side. “The targets seem to have been tipped off,” an American official told the Times. “There are indications that some senior Pakistani officials aren’t happy about it, and neither are we, of course.”

A senior Pakistani official said on Saturday that Pakistan was not suspicious that the bomb makers had disappeared, because “extremist groups often move locations.” But then he added that “now that the U.S. side has drawn our attention to the possibility of the Taliban being tipped off between the day the intelligence was shared and the day of our military action, we will work on finding out what happened.”

But these accusations only increase tensions in an already tense situation. The U.S. remains suspicious of Pakistani intelligence after the discovery of bin Laden. Departing defense secretary Robert Gates said recently that he thought “somebody” in Pakistan knew. Pakistan, in turn, saw U.S. attacks as a breach of its sovereignty. A security source in Islamabad told the Telegraph that Panetta had used the collusion accusation to underscore why the U.S. distrusted Pakistan and needed its own independent operations inside the country. In the meeting, Panetta also asked for Islamabad to reverse a decision to scale back the number of American military officers in the country.

The tensions in Pakistan seem to be manifesting in further violence in the region. On Sunday, while Panetta was in Islamabad, two bombs exploded minutes apart in the northwest Pakistani city of Peshawar, killing at least 34 people and wounding nearly 100. According to IslamOnline, the Pakistani Taliban, despite vowing to carry out attacks to avenge bin Laden, denied any role in the bombing and said they target only the government and military.