A brewing political controversy could turn into a parliamentary one after the Liberals introduced a motion Thursday to force the government into releasing secret documents in the Afghan detainee affair.

Liberal Leader Michael Ignatieff said the government has censored documents with "Soviet zeal," and should immediately release any records relating to an incident of torture which was documented by Canadian troops.

The motion passed in Parliament by a vote of 145-143, forcing the Tories to release the documents. However, if the Tories don't release the reports, Canada's courts might have to intervene on the case, which could centre on arguments of parliamentary privilege and national security.

The parliamentary maneuvering follows revelations by Gen. Walt Natynczyk, who said Canadian troops captured a man and handed him over to Afghan police, only to later see him being beaten.

The third Geneva Convention mandates that transferring prisoners who are then tortured is a war crime.

Though Natynczyk has called a military inquiry, MPs said that launching an internal investigation is not enough, because the military would be equal to both the accused and the jury.

"For over a year, the Conservatives had credible reports of torture from Canadian diplomats and soldiers in the field--and they did nothing," Ignatieff said.

"They must account for that year of willful blindness. Their refusal to get to the truth is costing us our credibility on human rights, and is a threat to the honour of Canada, which our troops so bravely uphold every day that they serve."

Earlier in the day, opposition MPs demanded the resignation of Defence Minister Peter MacKay and a public inquiry into the affair.

"It's time for this government to take the step that's required and that's to ask the minister to step down and start the inquiry, independently," said NDP Leader Jack Layton.

The demands in Ottawa came as the Conservative government continues to face heated questions over its insistence that the Canadian Forces never knowingly put Afghan detainees at the risk of torture.

Natynczyk revealed that in June 2006, Canadian troops captured a man and handed him over to Afghan police, only to find out that he was mistreated and beaten. The Canadians then took the man back into their custody.

Bloc Quebecois leader Gilles Duceppe pointed to a 2006 report by a Canadian commander in Afghanistan that stated photos were taken of detainees before handing them over to Afghan authorities. Duceppe said this was "in order to have evidence of mistreatment because, I quote 'it has happened in the past.'"

Duceppe alleged that the government knew about the abuse for "quite some time."

However, Prime Minister Steven Harper said the report was evidence that the Canadian government took action to prevent the abuse, and that the issue was dealt with up to four years ago. He accused the opposition MPs of attacking Canadian soldiers.

"Canadian forces, when faced with a case of abuse, took immediate action to deal with that ... that should hardly be used as a reason to attack the forces, it should be used as a reason to praise them."

The day before the revelation, Natynczyk said that Canadian troops had only questioned the photographed man, not captured him. But after reviewing the file with his staff, the general called a news conference to release the correct information.

Natynczyk also said the military inquiry would determine why neither he, or his predecessor Rick Hillier, saw a platoon commander's report which detailed the prisoner's capture.

Liberal defence critic Ujjal Dosanjh said the government cannot claim that Natynczyk's announcement yesterday was the first time it learned about this specific incident of detainee abuse.

Further questions

Ottawa law professor Errol Menders said the incident report forms "incontrovertible proof" that Canada should have immediately ceased transfers to Afghan authorities, a decision which the government is ultimately responsible for.

"If these guys had no clear instructions, and it's clear they didn't, they were almost making it up on the fly which shows you the civilian command was putting them into an untenable position," Mendes said.

The revelation by Natynczyk led opposition members to attack the Conservative government and MacKay, who has said "there is not a single, proven allegation" of abuse prior to 2007.

When MacKay appeared before the special House of Commons committee on Wednesday, he said it was "an outrageous, false, inflammatory and insulting allegation" from a fellow MP.

He also said that "no one ever turned a blind eye. Let me be clear, the government of Canada has never been complicit in torture or any violation of international law by willfully allowing prisoners taken by the Canadian forces to be exposed to abuse."

Richard Colvin, the diplomat who testified last month that the Conservative government was indifferent to his warnings of torture, is preparing a letter for the House of Commons committee to respond to statements made by the government in recent weeks.

The Conservative government initially responded to Colvin's allegations by trying to discredit him, a tactic that prompted a backlash from other diplomats and from opposition members. MacKay first said there were "incredible holes" in Colvin's allegations, though the defence minister has recently said his attacks on the ex-diplomat's allegations were not personal.

With files from The Canadian Press