|Pakistanis held daily protests against the NATO strike, with some calling on Islamabad to cut ties with US [AFP]
The Pakistani military has called the NATO cross-border air attack on a military checkpoint that killed 24 soldiers a deliberate act of aggression.
In a briefing to editors carried in local newspapers on Wednesday, Ishfaq Nadeem, director-general of military operations, said NATO forces were alerted they were attacking Pakistani posts, but helicopters kept firing at them.
Al Jazeera's Imtiaz Tyab, reporting from Islamabad, described Nadeem's detailed account of NATO's attack in the early hours of Saturday morning.
"[Nadeem] said two of their posts were attacked by the alliance forces for 15 minutes. They [Pakistani army] called NATO and informed their counterparts on the other side of the border that they were being attacked," he said.
"What happened next was interesting because they [NATO] stopped [attacking] and then, only 15 minutes later, these helicopters came back and attacked the [Pakistani] checkpoints again.
"The Pakistanis said they did retaliate, they fired mortars and anti-aircraft shells, but that wasn't enough to turn the helicopters around."
The Pakistani general's remarks come on top of the country's announcement of a boycott of an international conference in Germany on Afghanistan's future next week.
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.
Hillary Clinton, the US secretary of state, voiced regret on Wednesday over Pakistan's decision and urged it to reconsider.
Speaking at South Korea, Clinton said that the US stance that the border killing of Pakistani soldiers was a "tragic incident" and pledged an investigation "as swiftly and thoroughly as possible".
"Frankly this is regrettable that Pakistan has decided not to attend the conference in Bonn because this conference has been long in the planning," she said.
"Pakistan like the United States has a profound interest in a secure, stable and increasingly democratic Afghanistan," Clinton said.
Pakistan says the NATO attack on two combat outposts led to 13 people being wounded in addition to the deaths.
A YouTube video - said to show the aftermath of the NATO raid - has been shown on Pakistani television. It appears to show soldiers attending to the injured and the bodies of those killed in the attack.
Al Jazeera cannot independently verify the video's authenticity.
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.
|Pakistan held funerals for the slain soldiers on Friday
Al Jazeera's Tyab says that is much public anger in Pakistan over the attack.
"All across the country we have seen protests against the US," he said.
"People in Pakistan are saying they simply don't want the US to be in the region anymore. They want Pakistan to leave the so-called war on terror and break their alliance with US."
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.
NATO has 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 Clinton, 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.
Source: Al Jazeera and agencies