The United States stressed the “importance” of its ties with Pakistan after up to 26 soldiers were killed in cross-border Nato air strikes Saturday, plunging already frosty relations into crisis.
In a joint statement, US Secretary of Defense Leon Panetta and Secretary of State Hillary Clinton offered their “deepest condolences” and said they backed “Nato’s intention to investigate immediately.”
“Secretaries Clinton and Panetta have been closely monitoring reports of the cross-border incident in Pakistan today,” the statement said.
“Both offer their deepest condolences for the loss of life and support fully Nato’s intention to investigate immediately.”
Islamabad has ordered a review of all arrangements with the United States and Nato, including diplomatic, political, military and intelligence activities, following the deadly cross-border strikes.
The US-led Nato force in Afghanistan admitted it was “highly likely” that the force’s aircraft caused the pre-dawn deaths, inflaming US-Pakistani relations still reeling from the May killing of Osama bin Laden.
Pakistan also told the United States to vacate a remote air base reportedly used as a hub for covert CIA drone strikes on areas bordering Afghanistan, though US officials have said no US military personnel are based there.
Foreign Minister Hina Rabbani Khar on Sunday telephoned her US counterpart Hillary Clinton to convey Pakistan's "deep sense of rage" over cross-border NATO air strikes, the foreign office said.
Khar said that attacks like Saturday's strike on military outposts that left at least 24 Pakistani soldiers dead were "totally unacceptable" as they contravened international law and violated Pakistani sovereignty.
The Pakistani minister spoke to Clinton in the early hours of Sunday to inform her of decisions made by the Defence Committee of the Cabinet including blocking NATO supply routes, the foreign office said in a statement.
"The foreign minister conveyed to the secretary of state, the deep sense of rage felt across Pakistan at the senseless loss of 24 soldiers due to the NATO/ISAF attack on the Pakistani post," it said.
Khar said "such attacks are totally unacceptable. They demonstrate complete disregard for international law and human life, and are in stark violation of Pakistani sovereignty".
"This negates the progress made by the two countries on improving relations and forces Pakistan to revisit the terms of engagement," Khar added.
The statement said that Clinton offered her condolences over the loss of life, said she was deeply saddened by the event, and conveyed the US government's intention to work with Pakistan to resolve the issue.
Pakistani officials said on Saturday that NATO aircraft had killed at least 25 soldiers in strikes against two military posts at the northwestern border with Afghanistan, and the country’s supreme army commander called them unprovoked acts of aggression in a new flash point between the United States and Pakistan.
The Pakistani government responded by ordering the Central Intelligence Agency to vacate the drone operations it runs from Shamsi Air Base, in western Pakistan, within 15 days. It also closed the two main NATO supply routes into Afghanistan, including the one at Torkham. NATO forces receive roughly 40 percent of their supplies through that crossing, which runs through the Khyber Pass, and Pakistan gave no estimate for how long the routes might be shut down.
A NATO spokesman said it was likely that allied airstrikes caused the Pakistani casualties, but said an investigation had been ordered to determine the cause.
In Washington, American officials were scrambling to assess what had happened amid preliminary reports that allied forces in Afghanistan engaged in a firefight along the border and called in airstrikes. Senior Obama administration officials were also weighing the implications on a relationship that took a sharp turn for the worse after a Navy Seal commando raid killed Osama bin Laden near Islamabad in May, and that has deteriorated since then.
An attack by Nato aircraft on Pakistani troops that allegedly killed as many as 28 soldiers and looks set to further poison relations between the US and Pakistan was an act of self-defence, a senior western official has claimed.
According to the Kabul-based official, a joint US-Afghan force operating in the mountainous Afghan frontier province of Kunar was the first to come under attack in the early hours of Saturday morning, forcing them to return fire.
The high death toll from an incident between two supposed allies suggests Nato helicopters and jets strafed Pakistani positions with heavy weapons.
The deadliest friendly fire incident since the start of the decade-long war also prompted Pakistan to ban Nato supply trucks from crossing intoAfghanistan and to issue an order demanding the US quit the remote Shamsi airbase, from which the US has operated some unmanned drone aircraft.
A spokesman for Nato's International Security Assistance Force (ISAF) said it was "highly likely" that aircraft which had been called into the area to provide "close air support" to troops on the ground was responsible for causing casualties among the Pakistani soldiers.
For their part, a statement by the Pakistani military claimed that it was they who were attacked first, forcing them to respond to Nato's "aggression with all available weapons".