The deep suspicion that underlies every American move here is a fact of life that American officers say they must work through as they try to reverse the effects of the many years when the United States had cut Pakistan off from military aid because of its nuclear weapons program.

That time of estrangement, which lasted through the 1990s, left the Pakistanis feeling scorned and abandoned by the United States, and its military distant and seeded with officers and soldiers sympathetic to conservative Islam  and even at times the very militants they are today charged with fighting.

Today the American-led war in Afghanistan and its continuing campaign of drone strikes in Pakistan’s tribal areas have made the United States suspect at all levels of the military, and among the Pakistani population, as anti-Americanism has hit new heights. This training program is among the first steps to repair that relationship. “This is the most complex operating environment I’ve ever dealt with,” said Col. Kurt Sonntag, a West Point graduate who handed out the graduation certificates here.

Such are the limits on the Americans that dozens of Pakistani enlisted “master trainers,” taught by the Americans, do the bulk of the hands-on instruction here. Since January 2009, about 1,000 scouts from Pakistan’s Frontier Corps have completed the training, which is designed to help turn the 58,000-member paramilitary force that patrols the tribal areas from a largely passive border force into skilled and motivated fighters.

The personnel training is just one piece of what is now a multipronged relationship. With combating Al Qaeda and the Taliban now the overriding priority, the United States provides Pakistan with a wide array of weapons, shares intelligence about the militants, and has given it more than $10 billion toward the cost of deploying nearly 150,000 troops in and around the border areas since 2001  with the promise of much more to come.