The documents, obtained by the BBC, say western military commanders believe that Pakistan is helping guide attacks on coalition troops and that captured Taliban fighters are confident they'll take over Afghanistan once foreign troops leave.
The notion that Islamabad — or some elements of the country's military or intelligence service — are pulling the strings of the insurgency is not new, MacKay said following question period Wednesday.
But he suggested patience is wearing thin.
"If they are a reliable all, if they are a country that wants to see Canada, the United States, Great Britain and other NATO allies continue to work in the region to bring about peace and security throughout the region, then their co-operation is required and, in fact, it's demanded," MacKay said.
The report said Pakistan's advice and safe havens are critical to the Taliban, even if some Taliban commanders are uncomfortable taking instructions from the Inter-Service Intelligence agency, the Pakistan intelligence service.
There is also skepticism that the newly trained Afghan National Army will be able to handle the guerrilla force on its own — a perception that's hammered home in interviews with 4,000 captured Taliban, who boast that they're just biding their time until NATO leaves.
MacKay scoffed at that portion of the report.
"Naturally, it's going to reflect ... an overly optimistic view of what's happening on the ground in Afghanistan," he said.
"We continue to see fighters taken off the battlefield, their followers similarly are diminishing, their leadership is in disarray and the support for the Taliban in Afghanistan continues to fall."
The leaked document painted a more stark picture: "Despite numerous tactical setbacks, surrender is far from their collective mind set."
Pakistani Foreign Minister Hina Rabbani Khar, who's in Kabul for talks with the Karzai government, said the report consists of baseless allegations and old news churned up just as her country attempts to improve relations with its neighbours.
"We can disregard this as a potentially strategic leak. This is old wine in an even older bottle," Khar told reporters at a joint press conference with her Afghan counterpart.
In what could be construed as a vote of confidence in the Afghan army, U.S. Defence Secretary Leon Panetta revealed Wednesday that western forces will likely be out of combat by the end of 2013 and move more toward a training role.
He said American troops would "advise-and-assist."
Panetta's comments came on the eve of a NATO meeting in Brussels where Afghanistan is to be the main topic of conversation.
Earlier this week, the commander of the Canadian Army questioned whether western countries would have the political will — or cash to pay for the bulked up Afghan army after 2014.
Lt.-Gen. Peter Devlin said the continuing economic crisis in Europe and budget belt-tightening in North America could make the outlay of billions of dollars to sustain the 352,000 strong security force a tough sell.
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