http://www.washingtonpost.com/wp-dyn/content/article/2009/09/01/AR2009090103908.html

excerpts:

Senior U.S. commanders in eastern Afghanistan, where insurgent leader Jalaluddin Haqqani’s network is dominant, said that the sophistication of the insurgents’ attacks had increased markedly, beginning with bloody battles along the Pakistani border last summer. To many of the Americans, it appeared as if the insurgents had attended something akin to the U.S. Army’s Ranger school, which teaches soldiers how to fight in small groups in austere environments.

“In some cases . . . we started to see that enhanced form of attack,” said one Army general who oversaw forces in Afghanistan until earlier in the summer. As attacks in the east have increased this year, some officers have speculated that the insurgents are getting more direct help from professional fighters from Arab and Central Asian countries. These embedded trainers, the officers said, play almost the same role as U.S. military training teams that live with and mentor Afghan government forces.

…Remote areas where the Taliban has been fighting U.S. forces for years, such as the Korengal Valley near the border with Pakistan, “are a perfect lab to vet fighters and study U.S. tactics,” said a Pentagon officer. The insurgents have learned to gauge the response times for U.S. artillery cannons, as well as fighter jets and helicopters. “They know exactly how long it takes before . . . they have to break contact and pull back,” the officer said.