Pakistan blocks supply routes after US air strike kills troops

The incident was a major blow to American efforts to rebuild an already tattered alliance vital to winding down the 10-year-old Afghan war. Islamabad called the bloodshed in one of its tribal areas a “grave infringement” of the country’s sovereignty, and it could make it even more difficult for the US to enlist Pakistan’s help in pushing Afghan insurgents to engage in peace talks.

A Nato spokesman said it was likely that coalition air strikes caused Pakistani casualties, but an investigation was being conducted to determine the details. If confirmed, it would be the deadliest friendly fire incident by Nato against Pakistani troops since the Afghan war began a decade ago.

A prolonged closure of Pakistan’s two Afghan border crossings to Nato supplies could cause serious problems for the coalition. The US, which is the largest member of the Nato force in Afghanistan, ships more than 30 per cent of its non-lethal supplies through Pakistan.

The coalition has alternative routes through Central Asia into northern Afghanistan, but they are costlier and less efficient.

Pakistan temporarily closed one of its Afghan crossings to Nato supplies last year after US helicopters accidentally killed two Pakistani soldiers. Suspected militants took advantage of the impasse to launch attacks against stranded or rerouted Nato supply trucks.

The government reopened the border after about 10 days when the US apologised.

Pakistan announced the latest border closures to Nato in a statement issued after an emergency meeting of the cabinet’s defence committee, chaired by prime minister Yousuf Raza Gilani.

It also said that within 15 days the US must vacate Shamsi Air Base in south-western Baluchistan province. The US uses the base to service drones that target al Qaida and Taliban militants in Pakistan’s tribal region when they cannot return to their bases inside Afghanistan because of weather conditions or mechanical difficulty, said US and Pakistani officials.

The government also plans to review all diplomatic, military and intelligence co-operation with the US and other Nato forces.

Mr Gilani summoned US ambassador Cameron Munter to protest at the alleged Nato strike, said the Foreign Ministry, which described the attack as a “grave infringement of Pakistan’s sovereignty” which could have serious repercussions on Pakistan’s co-operation with Nato.

Mr Munter said he regretted any Pakistani deaths and promised to work closely with Islamabad to investigate the incident.

The White House said senior US civilian and military officials had expressed their condolences to their Pakistani counterparts.

The White House statement did not address Pakistan’s decision to block supply routes for the war in Afghanistan or its demand that the US vacate the drone base. The Pakistani army said yesterday that Nato helicopters and fighter jets carried out an “unprovoked” attack on two of its border posts in the Mohmand tribal area before dawn on Saturday, killing 24 soldiers and wounding 13 others. The troops responded in self-defence “with all available weapons”, an army statement said.

Pakistan army chief General Ashfaq Parvez Kayani condemned the attack.

A spokesman for Nato forces, Brig Gen Carsten Jacobson, said Afghan and coalition troops were operating in the border area of eastern Afghanistan when “a tactical situation” prompted them to call in close air support. It was “highly likely” that the air strikes caused Pakistani casualties.

The border issue is a major source of tension between Islamabad and Washington. Much of the violence in Afghanistan is carried out by insurgents based just across the border in Pakistan.

Coalition forces are not allowed to cross the frontier to attack the militants, who sometimes fire rockets across the line, reportedly from locations close to Pakistani army posts. The two posts attacked on Saturday were about 1,000 feet apart on a mountain top and were set up to stop Afghan-based Pakistani militants from mounting cross-border attacks..