WASHINGTON (AP) -- NATO forces may have been lured into attacking friendly Pakistani border posts in a calculated maneuver by the Taliban, according to preliminary U.S. military reports on the deadliest friendly fire incident with Pakistan since the Afghanistan war began.
The NATO airstrike killed 24 Pakistani soldiers over the weekend in an apparent case of mistaken identity, The Associated Press has learned.
A joint U.S.-Afghan patrol was attacked by the Taliban early Saturday morning. While pursuing the enemy in the poorly marked border area, the patrol seems to have mistaken one of the Pakistan troop outposts for a militant encampment and called in a NATO gunship and attack helicopters to open fire.
U.S. officials say the reports suggest the Taliban may have deliberately tried to provoke a cross-border firefight that would set back fragile partnerships between the U.S. and NATO forces and Pakistani soldiers at the ill-defined border. Officials described the records on condition of anonymity to discuss classified matters.
The incident has sent the perpetually difficult U.S.-Pakistan relationship into a tailspin.
On Tuesday, Pakistani Gen. Ashfaq Nadeem called the incident a "deliberate act of aggression" and said it was "next to impossible that NATO" did not know it was attacking Pakistani forces.
Gen. James Mattis, head of U.S. Central Command, announced Monday he has appointed Brig. Gen. Stephen Clark, an Air Force special operations officer, to lead the probe of the incident, and said he must include input from the NATO-led forces in Afghanistan, as well as representatives from the Afghan and Pakistani governments.
Nadeem said the Pakistani army had little faith that any investigation will get to the bottom of the incident and may not cooperate with it. He said other joint inquiries into at least two other similar -- if less deadly -- incidents over the last three years had "come to nothing."
Nadeem made the remarks during a briefing with Pakistani journalists and defense analysts in army headquarters. Foreign media were not invited, but two attendees relayed Nadeem's comments to The Associated Press.
According to the U.S. military records described to the AP, the joint U.S. and Afghan patrol requested backup after being hit by mortar and small arms fire by Taliban militants.
Before responding, the joint U.S.-Afghan patrol first checked with the Pakistani army, which reported it had no troops in the area, the military account said.
Some two hours later, still hunting the insurgents -- who had by then apparently fled in the direction of Pakistani border posts -- the U.S. commander spotted what he thought was a militant encampment, with heavy weapons mounted on tripods.
The joint patrol called for the airstrikes at around 2:21 a.m. Pakistani time, not realizing the encampment was apparently the Pakistani border post.
Records show the aerial response included Apache attack helicopters and an AC-130 gunship.
U.S. officials are working on the assumption the Taliban chose the location for the first attack to create just such confusion and draw U.S. and Pakistani forces into firing on each other, according to U.S. officials briefed on the operation.
At the White House, spokesman Jay Carney said President Barack Obama considers the Pakistani deaths a tragedy, and said the administration is determined to investigate.
The Pentagon released a four-page memo from Mattis directing Clark to determine what happened, which units were involved, which ones did or did not cross the border, how the operation was coordinated, and what caused the deaths and injuries.
Mattis also asked Clark to develop recommendations about how border operations could be improved, and said the final report should be submitted by December 23.
The details of the airstrike emerged as aftershocks were reverberating across the U.S. military and diplomatic landscape Monday, threatening communications and supply lines for the Afghan war and the success of an upcoming international conference.
While U.S. officials expressed regret and sympathy over the cross-border incident, they are not acknowledging blame, amid conflicting reports about who fired first.
The airstrike was politically explosive as well as deadly, coming as U.S. officials were working to repair relations with the Pakistanis after a series of major setbacks, including the U.S. commando raid into Pakistan that killed Osama bin Laden in May.
In recent weeks, military leaders had begun expressing some optimism that U.S.-Pakistan military cooperation along the border was beginning to improve. U.S. Army Maj. Gen. Daniel Allyn told Pentagon reporters just last Tuesday that incidents of firing from Pakistan territory had tapered off somewhat in recent weeks.
Speaking to reporters Monday, Pentagon press secretary George Little stressed the need for a strong military relationship with Pakistan.
"The Pakistani government knows our position on that, and that is we do regret the loss of life in this incident, and we are investigating it," said Little.
The military fallout began almost immediately.
Pakistan has blocked vital supply routes for U.S.-led troops in Afghanistan and demanded Washington vacate a base used by American drones. Pakistan ordered CIA employees to mothball their drone operation at Pakistan's Shamsi air base within two weeks, a senior Pakistani official said. The officials spoke on condition of anonymity to discuss intelligence matters.
On the diplomatic front, Pakistan said Tuesday it will boycott an international conference on Afghanistan next week to protest the incident.
The decision to boycott the Bonn, Germany, conference was made during a Pakistani Cabinet meeting in the city of Lahore, said three officials who attended the meeting. They spoke on condition of anonymity because they were not authorized to talk to the media ahead of an official announcement.
The State Department also issued a new warning for U.S. citizens in Pakistan. It said some U.S. government personnel working in Pakistan were being recalled to Islamabad and warned Americans to be on guard for possible retaliation. U.S. citizens in Pakistan are being told to travel in pairs, avoid crowds and demonstrations and keep a low profile.
Associated Press writers Lolita C. Baldor, Bradley Klapper and Pauline Jelinek contributed to this report.
AP Intelligence Writer Kimberly Dozier can be followed on Twitter (at)kimberlydozier.