So they've confirmed the long-suspected link. But Pakistan says they're just keeping track of what they're up to:

WASHINGTON — The Taliban’s widening campaign in southern Afghanistan is made possible in part by direct support from operatives in Pakistan’s military intelligence agency, despite Pakistani government promises to sever ties to militant groups fighting in Afghanistan, according to American government officials.

The support consists of money, military supplies and strategic planning guidance to Taliban commanders who are gearing up to confront the international force in Afghanistan that will soon include some 17,000 American reinforcements.

Support for the Taliban, as well as other militant groups, is coordinated by operatives inside the shadowy S Wing of Pakistan’s spy service, the Directorate for Inter-Services Intelligence, the officials said. There is even evidence that ISI operatives meet regularly with Taliban commanders to discuss whether to intensify or scale back violence before the Afghan elections.

Details of the ISI’s continuing ties to militant groups were described by a half-dozen American, Pakistani and other security officials during recent interviews in Washington and the Pakistani capital, Islamabad. All requested anonymity because they were discussing classified and sensitive intelligence information.

[...] But the inability, or unwillingness, of the embattled civilian government, led by President Asif Ali Zardari, to break the ties that bind the ISI to the militants illustrates the complexities of a region of shifting alliances. Obama administration officials admit that they are struggling to understand these allegiances as they try to forge a strategy to quell violence in Afghanistan, which has intensified because of a resurgent Taliban. Fighting this insurgency is difficult enough, officials said, without having to worry about an allied spy service’s supporting the enemy.

But the Pakistanis offered a more nuanced portrait. They said the contacts were less threatening than the American officials depicted and were part of a strategy to maintain influence in Afghanistan for the day when American forces would withdraw and leave what they fear could be a power vacuum to be filled by India, Pakistan’s archenemy. A senior Pakistani military officer said, “In intelligence, you have to be in contact with your enemy or you are running blind.”