U.S. military officials are endorsing an assessment by NATO's top commander in Afghanistan that says the mission in the war-torn country will fail without an increase in troops and resources.

Gen. Stanley McChrystal, the Afghan mission's NATO commander, said in a report posted Sunday on the Washington Post's website that NATO must change its strategy in Afghanistan and add more resources to the fight or risk defeat. The 66-page report was sent to U.S. Defence Secretary Robert Gates on Aug. 30.

In the report, McChrystal added that more troops are needed to fulfill the mission and the strategy must move away from focusing on military bases and into focusing on living in or near Afghan communities and interacting with locals.

Gen. David Petraeus, head of the U.S. Central Command, said that he and Joint Chiefs of Staff chairman Adm. Mike Mullen support McChrystal's "assessment and description."

"Obviously I endorsed the … assessment," Petraeus told a counterinsurgency conference in Washington on Wednesday.

An aide in Mullen's office has confirmed the chairman also endorses the assessment. Earlier this month, Mullen told Congress that it is "very clear" to him that more troops are needed in Afghanistan.

McChrystal is expected to submit a detailed request for more troops in Afghanistan before the end of the week, said Pentagon press secretary Geoff Morrell, a request that will reportedly ask for 40,000 more troops.

U.S. President Barack Obama has already ordered 21,000 additional U.S. troops to Afghanistan this year.

'Tactical success'

Lt.-Gen. Marc Lessard, commander of Canadian Expeditionary Force Command (CEFCOM) told The Canadian Press he agrees with McChrystal's assessment that the next year in Afghanistan will be critical.

"We are making tactical success in Kandahar but overall in the country and that's what Gen. McChrystal's saying — is if you're thinking long-term of establishing security, development and governance — we're a long way from establishing that," Lessard said.

Prime Minister Stephen Harper has said that Canada will still withdraw from Afghanistan in 2011 despite the assessment.

Opinion on if the U.S. should send more troops has been divided, with some Democrats coming out against the proposal.

Obama has been holding off on committing more troops to the country.

"It is simply premature to consider additional resources until Gen. McChrystal's assessment has been fully reviewed and discussed by the president and his team," Morrell said.

Policy debated warranted

McChrystal has denied that his assessment of the war in Afghanistan has caused a rift between the military and civilian leaders.

"A policy debate is warranted," McChrystal told the New York Times earlier in the week. "We should not have any ambiguities, as a nation or a coalition."

White House officials have been refocusing their efforts on Pakistan where al-Qaeda leaders are believed to be hiding, by potentially launching more missile strikes by unmanned spy planes and sending in more special operations forces.

Pakistan will not allow the United States to deploy a large-scale military troop buildup on its soil.

Republican Senator Kit Bond, who sits on the senate intelligence committee, said the focus on Pakistan must not come at the cost of the Afghanistan mission or be seen as a substitute for deploying more troops.

"While denying al-Qaeda and Taliban militants sanctuary in the border regions of Pakistan is critical, a counterterrorism-only approach focusing only on one part of this regional conflict will ultimately hand victory to the world's most violent and feared terrorists," said Bond.

With files from The Associated Press