Pakistani militants attacked trucks supplying NATO forces in neighboring Afghanistan as supplies piled up at a border crossing closed after Pakistan said coalition aircraft killed three of its soldiers.

Insurgents struck “40 trucks in the city of Shikarpur and 27 of them were completely destroyed,” Mir Aman Chandio, a police officer in southern Sindh province, where the raid took place, said by telephone. Some suspects have been detained, he said, without elaborating.

It wasn’t clear whether the convoy had been diverted due to Pakistan’s shutting yesterday of the main supply route into Afghanistan for what it said was an attack on a border post inside its territory by North Atlantic Treaty Organization aircraft. Pakistan’s Prime Minister Yousuf Raza Gilani today told parliament NATO must apologize, adding that if it doesn’t, the government has “other options.”

Half of all war supplies to Afghanistan pass through Pakistan, the U.S. military’s Transportation Command says.

“The border is still closed after the NATO attack yesterday,” said Zahirullah Khan, a local government official in Jamrood, part of Khyber Agency through which equipment for international troops fighting the Afghan Taliban flows. “Around 400 trucks are standing here waiting for the border to reopen.”

Missile Strikes

NATO acknowledged its forces entered Pakistan’s airspace as part of a raid on insurgents and responded to small arms fire, the International Security Assistance Force said in a statement yesterday.

The incident in the Upper Kurram region underscores tensions between the U.S. and Pakistani armed forces after the American military this month escalated the number of missile strikes against Taliban and al-Qaeda militants in northwest Pakistan’s tribal region.

Pentagon spokesman Colonel David Lapan told reporters yesterday that the closure of the northern route isn’t having an impact on supply of U.S. and NATO troops because the coalition has other land and air avenues into Afghanistan, including a land route in southern Afghanistan that remains open.

Pakistan Offensives

“We don’t put all our eggs in one basket,” Lapan said.

In yesterday’s incident, soldiers “retaliated through rifle fire to indicate that the helicopters were crossing into our territory,” Pakistan’s Inter Services Public Relations said in a statement. “Instead of heeding to the warning, helicopters went to fire two missiles, destroying the post.”

Pakistan’s Foreign Ministry on Sept. 27 protested after air strikes on its soil by NATO helicopters reportedly killed more than 50 people. It called the military action a violation of the United Nations mandate for U.S.-led forces in Afghanistan.

Pakistan’s army began an offensive against militants based in its rugged northwestern provinces last October. From the Taliban stronghold of South Waziristan, fighting has now spread to six tribal agencies in the region.

The U.S. wants Pakistan to target groups based in the remaining region, North Waziristan, that have attacked international troops in Afghanistan.

© Copyright 2010 Bloomberg News. All rights reserved.