A new level of cooperation includes Pakistani permission late last month for U.S. intelligence officials to station personnel and technology in this pulsating megacity, officials said. Intercepted real-time communications handed over to Pakistani intelligence officials have led to the arrests in recent days of Mullah Abdul Ghani Baradar, the Afghan Taliban's No. 2 commander, and two of the group's "shadow" governors for northern Afghanistan.  The detentions, which have taken place in a wave since early last week, were initially kept secret to allow intelligence operatives to use information gleaned from captures to draw additional militants into exposing their locations and movements, according to officials who discussed the ongoing operations on the condition of anonymity. Final agreement on the Karachi operation came during the last week of January, with the intercept system up and running by the first week of February.  "The ISI and the CIA are working together, with the Americans providing actionable intelligence and the Pakistanis acting together with them" to track down the insurgent leaders, a Pakistani official said, referring to Pakistan's Inter-Services Intelligence directorate.  The arrests offer stark evidence of something that has long been suspected: Top Afghan Taliban leaders have found refuge across Pakistan, particularly in its cities -- a fact the government here has long denied.  Pakistan's decision to go after the Afghan Taliban leadership reflects a quiet shift underway since last fall, said officials from both countries, who cited a November letter from President Obama to Pakistani President Asif Ali Zardari as a turning point.  The letter, which was hand-delivered by U.S. national security adviser James L. Jones, offered additional military and economic assistance and help easing tensions with India, a bitter enemy of Pakistan. With U.S. facilitation, the Indian and Pakistani foreign ministers have agreed to meet next week, the first high-level talks between the two countries since terrorist attacks in Mumbai in late 2008.  The letter also included an unusually blunt warning that Pakistan's use of insurgent groups to pursue its policy goals would no longer be tolerated. The letter's delivery followed the completion of a White House strategy review in which the administration concluded that stepped-up efforts in Afghanistan would not succeed without improved cooperation from Pakistan.  In explaining Pakistan's shift, sources also cited regular visits to Pakistan by U.S. officials, a boost in intelligence-sharing and assurances by Washington that a military push in southern Afghanistan would not spill into Pakistan. The United States also promised Pakistani officials that it has no intention of abandoning the region once that offensive ends.  Pakistan's agreement last month to allow expanded CIA interception operations follows a long period of estrangement between the U.S. intelligence agency and the ISI.  The CIA has long maintained that the ISI retained close ties with the Afghan Taliban as a way to hedge its bets against Indian influence in Afghanistan and the likelihood of an eventual U.S. departure.  Pakistan has detained prominent militants in the past, only to release them later. It was unclear Thursday to what extent the detained Taliban leaders were cooperating with their captors and whether the three may provide information that helps authorities apprehend others.
KARACHI, PAKISTAN -- The capture of senior Afghan Taliban leaders in Pakistan represents the culmination of months of pressure by the Obama administration on Pakistan's powerful security forces to side with the United States as its troops wage war in Afghanistan, according to U.S. and Pakistani o...