Kabul:
A United States military investigation has concluded that checks and balances devised to prevent cross-border mishaps with Pakistan failed to avert a deadly NATO airstrike last month in part because American officials did not trust Pakistan enough to give it detailed information about American troop locations in Afghanistan.
A report by the inquiry concluded that mistakes by both American and Pakistani troops led to airstrikes against two Pakistani posts on the Afghan border that killed 26 Pakistani troops. But two crucial findings - that the Pakistanis fired first at a joint Afghan-American patrol and that they kept firing even after the Americans tried to warn them that they were shooting at allied troops - were likely to further anger Pakistan and plunge the already tattered relationship between the United States and Pakistan to new depths.
In a statement and at a news conference here on Thursday, the Defense Department said that "inadequate coordination by U.S. and Pakistani military officers" and "incorrect mapping information" that NATO had provided to the Pakistani authorities capped a chain of errors that caused the debacle.
"This, coupled with other gaps in information about the activities and placement of units from both sides contributed to the tragic results," George Little, a Pentagon spokesman, told reporters.
The episode, the worst in nearly a decade riddled with fatal cross-border blunders, underscored gaping flaws in a system established in recent years to avoid such mistakes. American officials acknowledged that the policy of not divulging to Pakistan the precise location of allied ground troops in Afghanistan - for fear Pakistan might jeopardize their operations - contributed to the accident and underscored what the chief investigator called an "overarching lack of trust between the two sides."
On Nov. 25, the same day the episode began, Gen. John Allen, the allied commander in Afghanistan, met in Islamabad with Gen. Ashfaq Parvez Kayani, the Pakistani Army chief, to try to improve border coordination procedures.
Pakistan has insisted that its forces did nothing wrong, and that they did not fire the first shots. Rather, senior Pakistani military and civilian officials have accused the United States of intentionally striking the border posts, even after Pakistani officers called their counterparts to complain that their outposts were under allied attack.
Maj. Gen. Athar Abbas, the Pakistani military spokesman, said in a text message on Thursday: "The Pak Army does not agree with the findings of the US NATO inquiry as being reported in the media."
In an important detail that was not disclosed at the Pentagon briefing but is likely to further aggravate relations with Islamabad, an American officer in Afghanistan said the joint patrol of 120 Afghan and American Special Operations soldiers, operating along the often poorly demarcated frontier between Afghanistan and Pakistan, had come under Pakistani fire as it was entering an Afghan village, endangering civilians as well as the soldiers. The American officer said he believed that the Pakistanis had used night-vision technology because their shooting was unusually accurate, even though there were no casualties.
The Defense Department statement included an expression of regret, though it did not appear to go as far as the apology that Pakistani officials have demanded. "For the loss of life, and for the lack of proper coordination between U.S. and Pakistani forces that contributed to those losses, we express our deepest regret," it said.
A Pentagon spokesman, Capt. John Kirby, said the United States was prepared to make bereavement payments to families of the Pakistani soldiers who were killed. But a senior Pakistan security official in Islamabad said last week that Pakistan would refuse any "blood money."
Pentagon officials said Gen. Martin E. Dempsey, chairman of the Joint Chiefs of Staff, and Gen. James N. Mattis, head of the military's Central Command, called General Kayani on Wednesday to tell him that the inquiry was complete and to offer a briefing. It was unclear when that briefing would happen, American officials said.
In a telephone briefing with reporters here, Brig. Gen. Stephen A. Clark of the Air Force, who conducted the inquiry, said that both sides made mistakes.
According to a chronology by General Clark and other American military officials, the patrol planned to raid the village of Maya, about one mile inside Afghanistan's Kunar Province and near the Pakistani tribal area of Mohmand. Hiking up steep "goat trails" on a moonless night, the patrol came under heavy machine-gun fire from the ridge above at 11:09 p.m. on Nov. 25.
American officials said the first allied mistake was that NATO had not informed Pakistan about the patrol, so the Pakistani soldiers would not have known to expect allied forces nearby. NATO and Pakistani forces are supposed to inform each other about operations on the border precisely to avoid this kind of mistake.
After the allied ground force came under fire, the Americans tried to let the Pakistanis know that they were shooting at Americans. There was no direct verbal communication, but an AC-130 gunship fired flares and an F-15E fighter jet made a deafening, 600-mile-per-hour low-level pass in an effort to signal who they were.
Whether or not that message was understood was unclear, but the Pakistanis kept shooting.
As the Pakistanis continued to shoot, the AC-130 gunship opened fire for six minutes starting at 11:24 p.m. That was the result of a second error. That strike was set in motion when ground commanders believed they had been told no Pakistani troops were in the area. In fact, NATO was still checking.
From 11:44 p.m. until midnight, the AC-130 and Apache helicopter gunships resumed firing on "rudimentary bunkers," the report said.
About the same time, Pakistani officials called NATO to say their outposts were under attack. The NATO liaison then gave the Pakistani Army only a general location of the airstrike targets, and a wrong one at that because he had incorrectly configured his digital map.
"This goes back to the opening part of an overarching lack of trust between the two sides as far as giving out specifics, but it's also a very specific failure that occurred now that we have a firefight on our hands," General Clark said.
The Pakistanis made mistakes, too, he said. Pakistan never told NATO that it had established the border posts, which had been up for about three months. Pakistan has said it did tell NATO. Each side is supposed to inform the other when setting up new border positions.
Why the Pakistanis were firing remained unclear. Pakistan refused to participate in the inquiry, but General Clark acknowledged that he did not take into consideration news media reports on several detailed public briefings held by the Pakistani military in recent days.
A third engagement took place starting at 12:40 a.m., when a heavy machine gun began firing from the Pakistani side "a little further north" of the first Pakistani shooting. About 1 a.m., American officials finally confirmed the Pakistan presence at the posts, and firing ceased.
The joint patrol resumed its mission in the village, the American officer said, and seized one of the largest caches of weapons in Kunar Province this year, along with a bomb-making factory.