The US has expressed regret and offered its “deepest condolences” after 24 Pakistani soldiers who were killed in cross-border Nato air strikes were buried on Sunday, calling the attacks a “tragic unintended incident”.
Pakistani troops fired mortars at American ground soldiers patrolling the Afghan border, triggering Nato air strikes, according to Afghan officials and western sources. The killings, which occurred in the early hours of Saturday when Nato bombs smashed into two Pakistani military checkpoints, threaten to further damage the already shaky relationship between America and Pakistan.
Pakistan has responded to the killings by ordering the closure of a CIA drone base and by cutting Nato’s supply line into Afghanistan.
Details of what happened remain murky. Pakistan said the air strikes took place in the Pakistani tribal agency of Mohmand. Pakistani officials called the bombardment a “grave infringement” of the country’s sovereignty.
But The Sunday Times has learned that the two checkpoints hit by the air strikes were in fact constructed on Afghan soil, in Kunar province’s Khas Kunar district between the villages of Shaley and Shrunkey.
When American ground forces, who were conducting a night time patrol on Saturday morning, approached the two Pakistani checkpoints, the Pakistani soldiers stationed there responded by firing mortars at the Americans, according to local intelligence and western officials.
Standard operating procedures dictate that Nato forces must withdraw when fired upon by Pakistani troops, an occurrence which takes place more often than reported, according to western analysts who monitor security developments in the east.
But, on this occasion, Nato called in air strikes to stop the mortar teams from firing at the American ground troops.
“In the early night hours of this morning, a force consisting of Afghan forces and coalition forces, in the eastern border area where the Durand Line is not always 100 per cent clear, got involved in a fire fight,” said Nato spokesman, Brigadier General Carsten Jacobsen.
Pakistani troops have made an increasing number of cross-border incursions into Afghan territory since the beginning of the year, according to western and local Afghan officials.
Part of the problem is that the exact location of the border between the two countries, known as the Durand Line, remains disputed and ambiguous.
“It is still not clear if the Americans knew that the people attacking them were Pakistani military forces or whether they thought they might be insurgents. But the firing must have been intense for them to respond like this,” said one western official.
It is possible that the Americans may have mistaken the Pakistani soldiers for Taliban insurgents, especially because the operation took place in the dark. But officials said that the Americans would have known the location of Pakistani military bases along the border.
Pakistan’s army spokesman Major General Athar Abbas said map references of all of the force’s border posts had been given to NATO several times.
Other sources, who refused to be named because of the sensitivity of the subject, blamed the killings on the close relationship between elements of Pakistan’s security forces, such as the country’s Frontier Corps, and the insurgents based on Pakistani soil.
“The US could be hiding the fact that sometimes it can be quite difficult to discern Talibs from Frontier Corps given they often work closely together on operations and that one may be wearing the uniform of the other,” said one source.
Pakistan’s military denies that its forces fired on the Americans first. Pakistani officials said that Nato’s attack was “unprovoked” and that its soldiers were asleep when the air strikes hit the two bases, killing as many as 28 and wounding as many as 14, some critically.
The Afghanistan-Pakistan border region holds a highly volatile mixture of competing insurgent networks, American troops and special forces, CIA bases and Pakistani military outposts.
Much of the violence inside Afghanistan is carried out by militants who are based across the border in Pakistan.
Nato ground troops are forbidden from crossing the border to attack the militants’ havens, although the CIA is believed to run a 3,000 strong Afghan paramilitary force that conducts cross-border raids into Pakistan.
Afghan officials frequently accuse the Pakistani army of firing artillery across the border, killing Afghan civilians.
Militants based in Pakistan also fire mortars and rockets across the border, sometimes from locations close to Pakistani military outposts. American officials accuse Pakistan of turning a blind eye to these attacks.
But Islamabad has also criticised Nato for failing to prevent militants sheltering on the Afghan side of the border from attacking Pakistani security forces.
In response to the killing of its soldiers on Saturday, Pakistan closed the border crossings at Torkham in the east and Chaman in the south, preventing Nato supplies from crossing into Afghanistan. Nato relies on the border crossings for almost 50% of its supplies.
Pakistani officials have also demanded that America vacates its Shamsi Air Base in the southwest province of Balochistan. The airbase is used by the CIA for its controversial drone programme. The unmanned planes allow America to strike Al-Qaeda, Taliban and Haqqani militants inside Pakistan’s tribal agencies.
Relations between Pakistan and American hit an all time low earlier in the year when American Special Forces killed Osama bin Laden close to a Pakistani military academy near Islamabad.
Relations were again strained when senior American officials accused Pakistan’s intelligence service, the ISI, of supporting the Haqqani network, an insurgent group it blamed for attacking the US embassy in September.
The killings are not the first time that Pakistani and American forces have clashed along the rugged, mountainous border region.
In 2008, Pakistani soldiers fired heavy machine guns at two American helicopter gunships that had entered Pakistani airspace from Afghanistan. The helicopters were forced to turn back.
Four days later, American ground troops opened fire on Pakistani troops when the latter again shot at two US reconnaissance helicopters. The Americans said the helicopters were flying in support of a ground patrol on the Afghan side of the border.
Last year, American helicopters fired missiles at a base of Frontier Corp troops, killing three Pakistani soldiers and wounding three more, after Pakistani forces fired warning shots at the helicopters, which had entered Pakistani airspace. Pakistan responded by closing a key NATO supply route for 11 days.
Nato said it would launch an investigation into the most recent killings – the highest death toll caused by a “friendly fire” incident since the Afghan conflict began. The investigation is expected to ascertain whether Pakistani troops fired at American ground forces first.
The Pakistani government said it plans to review all diplomatic, military and intelligence cooperation with the US and other NATO forces following an emergency cabinet meeting chaired by Prime Minister Yousuf Raza Gilani.