US-Pakistan relations are handing by a thread after the NATO attack A US-led investigation into a NATO air strike that killed 24 Pakistani troops near the Afghan border will report its initial findings by December 23, officials said on Tuesday.The chief of US Central Command , which oversees US forces in Afghanistan and the Middle East, appointed Brigadier General Stephen Clark, a one-star air force general, to lead the investigation, the US military announced.
 The probe is expected to provide an initial report by December 23, it added.
Pakistan’s Prime Minister Yusuf Raza Gilani ruled out “business as usual” with the United States on Monday after the NATO attack, and the army threatened to drastically curtail cooperation with Washington on Afghanistan.
Saturday’s incident on Pakistan’s border with Afghanistan complicated US attempts to ease a crisis in relations with Islamabad and stabilise the region before foreign combat troops leave Afghanistan.
“Business as usual will not be there, therefore we have to have something bigger so that to satisfy my nation, the entire country,” Gilani told CNN when asked if ties with the United States would continue.
Gilani’s comments reflect the fury of the Pakistani government and military, and the pressure they are under from their own people. “You cannot win any war without the support of the masses,” he said. “We need the people with us.”
The relationship, he said, would continue only if based on “mutual respect and mutual interest.” Asked if Pakistan was receiving that respect, Gilani replied: “At the moment, not.”
 Pakistan responded with fury, cutting off crucial supply routes to NATO forces in Afghanistan, and ordering US personnel to vacate an air base reportedly used by CIA drones and a review of US relations.
 Brigadier Clark will lead the investigation with input from NATO and its International Security Assistance Force, which has 130,000 troops in Afghanistan in addition to an extra 10,000 American forces operating under separate command.
The Afghan and Pakistani governments are also being invited to take part, despite Pakistan\'s furious response to the attack.
 \"It is USCENTCOM\'s intent to include these government representatives to the maximum extent possible to determine what happened and preclude it from happening again,\" the US military said.
 \"The investigation team will focus their efforts on the facts of the incident and any matters that facilitate a better understanding of the circumstances surrounding the deaths and injuries of the Pakistani forces.\"
 ISAF sent an initial assessment team to the border over the weekend.
 A Western military official in Kabul, speaking on condition of anonymity, said the probe team had yet to arrive in Afghanistan but insisted its findings would be reported \"way quicker\" than initially expected.
The source said it was not unusual for US Central Command to carry out this kind of investigation rather than ISAF, which usually undertakes probes into incidents such as civilian casualties.
  ISAF refused to comment when asked whether US Special Forces had been operating in the area when the air strikes were called in.
Gilani’s comments cap a day of growing pressure from the Pakistani military, which threatened to reduce cooperation on peace efforts in Afghanistan.
“This could have serious consequences in the level and extent of our cooperation,” military spokesman Major General Athar Abbas told Reuters.
Pakistan has a long history of ties to militant groups in Afghanistan so it is uniquely positioned to help bring about a peace settlement, a top foreign policy and security goal for the Obama administration.
Washington believes Islamabad can play a critical role in efforts to pacify Afghanistan before all NATO combat troops pull out in 2014, and cannot afford to alienate its ally.
Adding a new element to tensions and a diplomatic boost for Islamabad, Pakistan’s ally China said it was “deeply shocked” by the incident and expressed “strong concern for the victims and profound condolences for Pakistan.”
Russia, which has been seeking warmer relations with Pakistan as worry grows over the NATO troop pullout in Afghanistan, said it was “unacceptable” to violate the sovereignty of states even when hunting “terrorists.”
 Islamabad insists that the air strikes were unprovoked, but Afghan and Western officials have reportedly accused Pakistani forces of firing first.
 Before Saturday\'s attack, US military officers had been working to shore up cooperation with Pakistani forces along the Afghan border.
 Communication between units on the border virtually broke down in the aftermath of a US raid in May that killed Al-Qaeda chief Osama bin Laden at his Pakistani compound, sending US-Pakistani relations into free fall.