Anti-American sentiment was running high Sunday in Pakistan, which shut its roads to US military supplies in protest at the killing of 24 of its soldiers in a NATO airstrike at the Afghan border a day earlier, dpa reported.
Foreign Minister Hina Rabbani Khar informed US Secretary of State Hillary Rodham Clinton that Islamabad had decided to close NATO supply routes and ordered the vacation within 15 days of an airbase used by the US military.
The two NATO supply routes in the south-western province of Baluchistan and the north-western tribal district of Khyber Agency are used to move about 40 per cent of all NATO supplies delivered to Afghanistan.
Reliance on those routes has been reduced in recent years, with NATO seeking to establish alternative routes through central Asian states.
Pakistan's military chief, General Ashfaq Parvez Kayani, attended the funeral of the victims in Peshawar, capital of the north-western province of Khyber-Pakhtunkhwa.
NATO helicopters and jets attacked two border posts Saturday in Mohmand Agency, one of the seven Pakistani tribal districts.
Pakistani officials said two officers and 22 soldiers were killed and 13 were wounded in what they described as unprovoked action.
However, an Afghan military official said NATO coalition forces responded after coming under attack from the Pakistani side first.
"The international forces were attacked first from an area near to the Pakistani paramilitary checkpoint. So they called for an airstrike," said the official, who asked not to be named.
German Foreign Minister Guido Westerwelle telephoned Khar on Sunday and offered medical treatment for the wounded, aides in Berlin said. He said Germany expected NATO and commanders in Afghanistan to hold a full investigation.
Khar said the attacks "negate the progress made by the two countries on improving relations."
The attacks "demonstrate complete disregard for international law and human life, are in stark violation of Pakistani sovereignty, and force Pakistan to revisit the terms of engagement," she said.
Pakistan has also lodged a protest with Afghanistan.
NATO's secretary general offered his condolences to Pakistan's prime minister, describing the airstrike as a "tragic unintended incident."
"I have written to the prime minister of Pakistan to make it clear that the deaths of Pakistani personnel are as unacceptable and deplorable as the deaths of Afghan and international personnel," Anders Fogh Rasmussen said.
"This was a tragic unintended incident. I fully support the ISAF investigation which is currently under way. We will determine what happened, and draw the right lessons," Rasmussen said.
In an unusual joint statement issued on Saturday, Clinton and US Defence Secretary Leon Panetta offered their "deepest condolences" for the deaths and said they "support fully NATO's intention to investigate immediately."
The latest airstrike has further strained already difficult relations between Pakistan and the United States. Ties have been uneasy since the May 2 killing of Osama bin Laden in a US raid in the north-western Pakistani city of Abbottabad.