KARACHI, Pakistan — Pakistan on Saturday blocked supply routes for U.S.-led troops in Afghanistan and announced it would end the use of a Pakistani airbase by American forces, in retaliation for a NATO attack on a Pakistani border outpost that officials said killed at least 24 soldiers and injuring another 13.
American forces were given 15 days to vacate the remote Shamsi airbase, which was secretly turned over to them after the 9/11 attacks. The decision to order the Americans out followed an emergency meeting of Pakistan's top civilian and military leadership late Saturday to decide how to respond to the deaths of the soldiers.
Shamsi was used for launching the war in Afghanistan in late 2001, then later served as the base for the U.S. drone program targeting militants. Set in desert in sparsely populated Baluchistan province in Pakistan's west, the airbase became highly controversial within Pakistan for its association with drone strikes, which Pakistan officially condemns.
The decision to expel the Americans, made by the country's leadership meeting as the Defense Committee of the Cabinet, was an admission that Shamsi remains in American use.
The committee also announced that the government would "revisit and undertake a complete review of all program, activities and cooperative arrangements" with the United States and U.S.-led forces in Afghanistan, "including diplomatic, political, military and intelligence".
Relations between Islamabad and Washington were already under deep strain before the incident, in which helicopters from the International Security Assistance Force (ISAF) operating in Afghanistan shelled check points on the Pakistani side, apparently in error.
"These attacks, which constituted breach of sovereignty, were violative of international law and had gravely dented the fundamental basis of Pakistan's cooperation with NATO/ISAF against militancy and terror," said a statement issued late Saturday by the committee, which is chaired by the prime minister and includes the army chief. "NATO/ISAF attacks were also violative of their mandate which was confined to Afghanistan."
The deaths of the Pakistani soldiers will pour fuel on the already raging anti-American sentiment in this key U.S. ally. Although there have been previous deaths of Pakistani troops caused by mistaken fire from coalition aircraft, the scale of the bloodshed this time was far greater. A statement from the Pakistani army chief, Gen Ashfaq Kayani, put the death toll at 24. Other reports put the number killed as high as 28.
The border between Pakistan's tribal area and Afghanistan is poorly marked. Insurgents, who use the tribal area as a safe haven, often fire on coalition and Afghan troops from positions close to Pakistani check points, raising U.S. suspicions that the Pakistani military collaborates with the insurgents.
The attack took place in the early hours of Saturday morning, around 2 a.m. local time, at an outpost on a mountain about 1.5 miles from the border, in the Mohmand part of the tribal area. Mohmand borders both Kunar and Nangarhar provinces in eastern Afghanistan, both areas where the Taliban is active.
The defense committee also officially confirmed that the supply routes for the coalition through Pakistan had been stopped. Around half the supplies for international troops in Afghanistan pass by road through Pakistan. Pakistani television showed lines of trucks carrying containers lined up at the border.
Two years ago, following a similar border incident that killed two Pakistani soldiers after they were mistaken for insurgents, Pakistan closed the border for 10 days.
Earlier in the day, the U.S. ambassador in Islamabad, Cameron Munter, was summoned to Pakistan's foreign ministry for an official protest.
Munter said in a statement that he had pledged that the "United States will work closely with Pakistan to investigate this incident", though neither he nor the American general in charge of coalition troops in Afghanistan, Army Gen. John R. Allen, admitted causing the deaths or provided any details of what happened.
Allen had visited Islamabad only a day earlier with Pakistan's army chief, Gen Ashfaq Kayani, for talks "aimed at enhancing border control on both sides."
The international coalition and the Pakistan military have poor communication at the border and their maps of the border line and the location of Pakistani check points don't always match.
Pakistan had previously announced that it would expel the Americans from Shamsi, which was never carried out. This time it seemed serious.
While Pakistan officially condemns the operation of U.S. drone aircraft over its territory, it quietly continues to co-operate with aspects of the drone program. It is believed that drones still fly out of Shamsi, but it is unclear whether they are armed or purely surveillance drones now.
Most drone flights now take place from an airbase at Jalalabad in Afghanistan.
Following a series of bitter disputes this year, U.S.-Pakistan military and intelligence co-operation had already been scaled back hugely. Pakistan ended a U.S. training program in counter-insurgency for Pakistani soldiers and ordered a substantial reduction in CIA personnel and activities allowed in the country.
Relations were shattered first by the furor surrounding a CIA contractor who shot dead two Pakistanis in Lahore, then in May when U.S. special forces, without notifying Pakistani officials in advance, raided a housing compound in northern Pakistan and killed Osama bin Laden.
Pakistan-U.S. relations have also been challenged this year by U.S. accusations that Pakistan's spy agency, the Inter-Services Intelligence Directorate, supports Taliban-allied insurgent who've attacked U.S. targets in Afghanistan. Pakistan has denied any links to the attacks.
(Shah is a McClatchy special correspondent.)
MORE FROM MCCLATCHY
Follow McClatchy on Twitter.