Pakistan will boycott an international conference on the future of Afghanistan in Germany next week, according to government officials.
The decision, announced on Tuesday, is in protest against a NATO cross-border attack on Saturday that killed 24 Pakistani soldiers.
The Bonn conference is aimed at bringing all major stakeholders together in securing a peaceful Afghanistan after NATO combat troops leave at the end of 2014.
"Pakistan has decided not to attend the Bonn conference as a protest," a government official told the Reuters news agency after a cabinet meeting chaired by Yousuf Raza Gilani, the Pakistan prime minister, in Lahore.
A second government official, who also asked not to be identified, confirmed the decision, viewed as the latest attempt by Pakistan to put pressure on the US, Afghanistan and NATO.
Mark Toner, the US state department spokesman, said: “We hope that they do in fact attend this conference because this is a conference that is about Afghanistan and building a more stable and prosperous and peaceful Afghanistan. And so that is very much in the interests of Pakistan."
Pakistan says the attack on two combat outposts led to 13 people being wounded in addition to the deaths.
Pakistan shut NATO's supply routes into Afghanistan and ordered the US to leave an airbase in the southwest of the country immediately after the attack.
The checkpoint that was attacked had been recently set up in the Mohmand tribal area by the Pakistan army to stop Taliban fighters holed up in Afghanistan from crossing the border and staging attacks, according to two government administrators in Mohmand, Maqsood Hasan and Hamid Khan.
NATO described the killings as a "tragic, unintended incident". US officials say a NATO investigation and a separate US one will seek to determine what happened.
The US investigation will provide initial findings by December 23, military officials said.
Earlier, Pakistan's foreign minister told the US of her "deep sense of rage" after NATO said it was probably to blame for the incident.
In a telephone conversation with Hillary Clinton, the US secretary of state, on Sunday, Hina Rabbani Khar said the attack was "totally unacceptable".
"They demonstrate complete disregard for international law and human life, and are in stark violation of Pakistani sovereignty," she said.
General Carsten Jacobson, a spokesperson for the NATO-led alliance in Afghanistan, confirmed on Saturday that it was "highly likely" the alliance's aircraft killed Pakistani soldiers.
"Close air support was called in, in the development of the tactical situation, and it is what highly likely caused the Pakistan casualties," Jacobson told Reuters.
NATO chief's remarks
Anders Fogh Rasmussen, the NATO chief, said he had written to Gilani to express regret over the "tragic, unintended" deaths.
"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," he said in a statement.
"This was a tragic unintended incident."
The incident comes at the closing days of a year that saw a US raid in the military town of Abottabad to capture and kill Osama bin Laden, the jailing of a CIA contractor and US accusations that Pakistan backed an attack on the US embassy in Kabul.
An increase in US drone strikes on armed groups in the last few years has also angered Islamabad, which says the campaign kills more Pakistani civilians in the border area than fighters.
The US disputes that, but declines to discuss the drone campaign in detail.
Source: Al Jazeera and agencies