The Pakistani Army on Friday rejected a U.S. investigation that concluded mistakes on both sides led to American airstrikes last month that killed 24 Pakistani soldiers and severely damaged the already strained relationship between the two countries.

The response indicates the report will do little to ease tensions, a worrying development for the U.S. because Pakistan’s cooperation is critical for the Afghan war. The Pakistani Army has said its troops did nothing wrong and claimed the attack was a deliberate act of aggression.

Pakistan has retaliated by closing its Afghan border to supplies meant for NATO troops in Afghanistan and kicking the U.S. out of a base used by American drones. NATO officials have said the closure of the supply route has not affected operations so far, but it would eventually if not reversed.

The Army “does not agree with the findings of the U.S./NATO inquiry as being reported in the media,” the force said in a short statement sent to reporters shortly after Friday midnight. “The inquiry report is short on facts.”

The Army will provide a detailed response after officials receive the report, it said. Pakistan refused to cooperate in the investigation.

Even though U.S. officials on Thursday accepted some of the blame for the attack on two Army posts along the Afghan border, they did not apologise for the incident, as many Pakistanis have demanded. Instead, the U.S. said its forces were fired on first and acted “with appropriate force” in self-defence.

Brig. Gen. Stephen Clark, an Air Force special operations officer who led the investigation, also said in a Pentagon briefing that U.S. forces did not know that the two relatively new Pakistani outposts spare structures constructed with stacked gray stones had been set up on the border.

The Pakistanis have disputed both of these points, saying its troops did not fire first and that it had given NATO maps that clearly marked where the outposts were located on a mountain ridge in the Mohmand tribal area.

Brig. Gen. Clark acknowledged that the U.S. had not informed Pakistan that American and Afghan commandos were conducting an overnight operation in Afghanistan on November 25-26 when the attack occurred. U.S. and NATO commanders believe that some of their military operations have been compromised when they’ve given details and locations to the Pakistanis, he said.

There is “an overarching lack of trust between the two sides” that keeps them from giving each other specific details on troops or combat outpost locations, Brig. Gen. Clark said as he went through a blow-by-blow account of the incident.

He also said U.S. forces failed to determine who was firing at them and whether there were friendly Pakistani forces in the area because they used inaccurate maps and mistakenly provided Pakistan with the wrong location where the fighting was taking place.

Pakistan could seize on these admissions to lower the temperature on the crisis, but it may be difficult for the army to walk back from the categorical positions it has taken. The attack has enraged the Pakistani public, especially anti-American hardliners. Over 30,000 Islamists staged a rally against the attack on Sunday.

Pentagon officials said on Thursday that military leaders had spoken by phone to Pakistan Army chief Gen. Ashfaq Pervez Kayani about the report’s conclusions, but have not yet given him a detailed briefing.

In Kabul, Defence Ministry spokesman Mohammad Zahir Azimi said the Afghan government would not comment on the U.S. report.

The deadly incident was the latest blow to the relationship between Pakistan and the U.S., which has been hit by a series of crises this year. A CIA contractor shot and killed two Pakistanis in the eastern city of Lahore in January, setting off a storm of anti-American protests.

This anger was compounded by the U.S. raid that killed Osama bin Laden in a Pakistani garrison town in May. The Pakistanis were outraged by the operation because they were not told about it beforehand.

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