Amid new allegations of Afghan detainees being mistreated at the hands of their jailers, the Opposition Liberals are demanding the Conservatives reveal just how many prisoners Canadian Forces have turned over to authorities in Afghanistan.

But Defence Minister Gordon O'Connor reiterated on Thursday that the information is a "matter of national security," and refused to cooperate.

"We do not intend to do anything to impede military operations in Afghanistan," O'Connor said during question period today, echoing a statement he made a day before in a joint meeting of the parliamentary committees on national defence.

After allegations of torture were levelled against Afghan security forces in April, Canada revised its procedures for transferring captured insurgents to Afghan authorities. Now, there are two new allegations of mistreatment of detainees by Afghan jailers.

This time, four prisoners handed over to the Afghans by Canadian troops have complained to Canadian authorities about abusive treatment during their detention. In the Commons, Liberal Ruby Dhalla accused the Conservatives of more confusion on the detainee issue.

"After repeatedly misleading this House, the ministers of defence, of foreign affairs, of public safety, were forced to admit that there are two new detainee capture cases," Dhalla said.

Foreign Affairs Minister Peter MacKay said it was only because of the new agreement Canada has arrived at with the Afghan government for unfettered access, that the new allegations came to light.

"We're following up with that in the process that's in place that includes consultation with the Afghan Independent Human Rights Commission and the Red Cross, as well as the Afghan government," he said.

Dhalla pointed out the American military releases details of prisoners it captures, and questioned why the Canadian military in Afghanistan cannot do the same.

"The U.S. issues a press release about every detainee they capture," she said in a statement directed at O'Connor. "Why does this minister refuse to be as transparent?"

O'Connor said each country involved in defence and reconstruction determines its own policies in Afghanistan.

"In the case of Canada, the military has determined that the public release of information on detainees would be detrimental to their military operations," he said.

"The operational chain of command has a responsibility for deciding what kind of information is releasable or not. It is a military decision, not a political decision."