Tensions between Pakistan and the United States are ratcheting dangerously close to a breaking point in the wake of a NATO airstrike that allegedly killed 24 Pakistani troops.
After Pakistan's closing of its northern border crossings in retaliation for the attacks, hundreds of trucks carrying supplies to U.S.-led troops in Afghanistan were stuck Sunday at the frontier, where they lay vulnerable to attack by militants.
The American relationship with Islamabad reached an all-time low when Pakistan also ordered the U.S. to vacate an air base that is used to launch American drones against al Qaeda and Taliban targets along the border.
Afghan officials said Sunday the airstrikes were called in by Afghan troops who had come under attack near the Pakistan border just before dawn on Saturday. The soldiers said they were fired upon from the direction of the two Pakistani border posts that were subsequently hit.
NATO said it is likely that its aircraft carried out the attack and has launched an investigation. The Pakistan-Afghanistan border is disputed and not marked in many areas.
NATO's top official, Secretary-General Anders Fogh Rasmussen, offered his "deepest condolences" on Saturday and said the coalition was committed to working with Pakistan to "avoid such tragedies in the future."
"We have a joint interest in the fight against cross-border terrorism and in ensuring that Afghanistan does not once again become a safe haven for terrorists," Rasmussen said in Brussels.
U.S. officials have promised to work closely with Pakistan as NATO carries out its investigation.
Even while Pakistan army chief Gen. Ashfaq Pervez Kayani attended the funerals of the victims, including a major, there were fears that militants could unleash attacks against the almost 300 stranded trucks that were ferrying crucial supplies to NATO troops in Afghanistan.
A year ago, 150 trucks were destroyed and many drivers injured in an attack by suspected militants after Pakistan closed an Afghan border crossing to NATO supplies for about 10 days in retaliation for a U.S. helicopter attack in which two Pakistani soldiers were killed.
"We are worried," said driver Saeed Khan, speaking by telephone from the border terminal in Torkham. "This area is always vulnerable to attacks. Sometimes rockets are lobbed at us. Sometimes we are targeted by bombs."
NATO ships about half of its non-lethal supplies to its troops in Afghanistan through Pakistan. Critical supplies, such as ammunition, are flown into Afghan bases.
On the diplomatic front on Sunday, Pakistani Foreign Minister Hina Rabbani Khar told U.S. Secretary of State Hillary Rodham Clinton by phone that the air attack negated all progress in improving the tattered alliance between the two countries.
According to a press release issued by the Pakistani prime minister's office, she said the attack was unacceptable, showed complete disregard for human life and has sparked outrage within Pakistan.
Still, a total break in the troubled relationship between the two countries appears unlikely because the Americans give Pakistan billions of dollars each year in military and civilian aid. Meanwhile, the U.S. is relying on Pakistan to push Afghan insurgents toward a peaceful resolution of the 10-year war.
With files from The Associated Press
