Pakistani Troops Fired First in NATO Attack
I believe the nearby eyewitness accounts. Afghan army and security forces within sight of the Pakistani outposts along the border. I believe Pakistan security forces, as poorly trained as they are, did attack NATO planes first.
According to the eyewitnesses, NATO attack aircraft were targeting Taliban insurgents, which were close to the Pakistani outposts located in the Wild West of lawlessness of the Mohmand tribal region. This is next door to Afghanistan's Kunar provice. Afghan army soldiers, who were nearby fighting those in the target area, called in for air support. As the planes made their bombing runs or fired their missiles, the poorly trained and frightened Pakistani security forces (which are lightly armed and generally ineffective) panicked and fired on the NATO aircraft. No doubt, the aircraft may have come close to the border area which does not have neon signs saying " Pakistan Border". The pilots noticed they were taking on fire from the ground via tracers from light antiaircraft rounds and simply attacked killing 25 men, thinking they were Taliban.
This sort of tactic by guerrilla fighters is common in these types of conflicts. This happened frequently in Vietnam, Enemy troops learned the tactics of US bombers and often would hug American bases or other areas, close to US troops. If the officer called in air support, often, only a few hundred yards separated the two forces. There could easily be collateral damage. If the enemy was hugging too close, airstrikes were verboten. In this case, the Taliban know full well of the tension between the US and Pakistan. They were exploiting it, hugging near a Pakistani outpost. The Afghan army was attacking it. Pakistani forces were observing this from their side. NATO airstrikes were called and may have appeared to the Pakistani forces that they were going to be attacked based on the aircraft approach and fired under panic. Afghan soldiers wondered why Pakistani troops were firing at the incoming NATO jets. NATO responded thinking the barely visible people to the pilot were Taliban.
End of story.