PESHAWAR, Pakistan — Pakistan on Saturday accused NATO helicopters of firing on two army checkpoints in the northwest and killing 25 soldiers, then retaliated by closing a key border crossing used by the coalition to supply its troops in neighboring Afghanistan.
The incident Friday night was a major blow to already strained relations between Islamabad and U.S.-led forces fighting in Afghanistan. It will add to perceptions in Pakistan that the American presence in the region is malevolent, and to resentment towards the weak government in Islamabad for co-operating with Washington.
It comes a little over a year after a similar but less deadly incident, in which U.S. helicopters accidentally killed two Pakistani soldiers near the Afghan border, whom the pilots mistook for insurgents. Pakistan responded by closing the Torkham border crossing to NATO supplies — as it did Saturday — for 10 days until the U.S. apologized.
In a statement sent to reporters, the Pakistan military blamed NATO for Friday's attack in the Mohmand tribal area, saying the helicopters "carried out unprovoked and indiscriminate firing."
NATO officials in Kabul said Saturday morning that they were aware of the reports, and would release more information after they were able to gather more facts about what happened.
Much of the violence in Afghanistan against Afghan, NATO and U.S. troops is carried out by insurgents that are based just across the border in Pakistan. Coalition forces are not allowed to cross the frontier to attack the militants, which sometimes fire artillery and rockets across the line.
American officials have repeatedly accused Pakistani forces of supporting — or turning a blind eye — to militants using its territory for cross-border attacks. The border issue is the major source of tension between Islamabad and Washington, which wants to stabilize Afghanistan and withdraw its combat troops there by the end of 2014.
The border is disputed in many areas and not clearly marked, adding to the difficulties faced by the different militaries in controlling it.
Pakistan state TV said the helicopters killed 25 Pakistani soldiers in the incident. Two government officials in Mohmand confirmed the death toll and said 14 other soldiers were wounded.
The helicopters attacked two checkpoints around 1,000 feet apart from each other, one of them twice, and two officers were among the dead, said a government official in Mohmand and a security official in Peshawar, the main city in Pakistan's northwest.
The officials all spoke on condition of anonymity because they were not authorized to talk to the media.
Ties between Washington and Islamabad had already taken an especially hard hit from the covert U.S. commando raid that killed Osama bin Laden in a Pakistani garrison town on May 2. The Pakistanis were outraged that they were not told about the operation beforehand, and now are angered even more than before by U.S. violations of the country's sovereignty.
In a statement, Prime Minister Yusuf Raza Gilani strongly condemned the alleged NATO attack, and said government was taking it up "in the strongest terms with NATO and the U.S.
A Pakistani customs official told The Associated Press that he received verbal orders Saturday to stop all NATO supplies from crossing the border through Torkham in either direction. A transporter who runs a terminal at the border where NATO trucks park before they cross confirmed the closure. They spoke on condition of anonymity because of the sensitivity of the matter.
Torkham runs through the famed Khyber Pass and is the main crossing to Afghanistan from Pakistan, the country through which NATO ships about 30 percent of the non-lethal supplies used by its Afghan-based forces. A short stoppage will have no effect on the war effort, but it is a reminder of the leverage Pakistan has over the United States from the supply routes to landlocked Afghanistan running through its territory.
The incident is also a reminder of the extreme volatility of the border.
The checkpoint that was attacked had been recently set up in Mohmand's Salala village by the army to stop Pakistani Taliban militants holed up in Afghanistan from crossing the border and staging attacks, said two local government administrators, Maqsood Hasan and Hamid Khan.
The Pakistani military has blamed Pakistani Taliban militants and their allies for killing dozens of security forces in such cross-border attacks since the summer. Pakistan has criticized Afghan and foreign forces for not doing enough to stop the attacks, which it says have originated from the eastern Afghan provinces of Kunar and Nuristan. The U.S. has largely pulled out of these provinces, leaving the militants in effective control of many areas along the border.
The Afghan government blamed Pakistan for firing hundreds of rockets into eastern Afghanistan earlier this year that killed dozens of people. The Pakistan army has denied it intentionally fired rockets into Afghanistan, but acknowledged that several rounds fired at militants conducting cross-border attacks may have landed over the border.
The Afghan and Pakistani Taliban are allies but have largely focused their attacks on opposite sides of the border. The Afghan Taliban aims to topple the U.S.-allied government in Kabul, and the Pakistani Taliban has tried to do the same in Islamabad.
The U.S. helicopter attack that killed two Pakistani soldiers on Sept. 30 of last year took place south of Mohmand in the Kurram tribal area. A joint U.S.-Pakistan investigation found that Pakistani soldiers fired at the two U.S. helicopters prior to the attack, a move the investigation team said was likely meant to notify the aircraft of their presence after they passed into Pakistani airspace several times.
Pakistan moved swiftly after the attack to close Torkham to NATO. Suspected militants took advantage of the impasse to launch attacks against stranded or rerouted trucks carrying NATO supplies.
Senior U.S. diplomatic and military officials eventually apologized for the attack, saying it could have been prevented with greater coordination between the U.S. and Pakistan. Pakistan responded by reopening the border crossing.
Abbot reported from Islamabad. Associated Press writer Anwarullah Khan contributed to this report from Khar, Pakistan.