U.S. Defence Secretary Robert Gates, left, and Defence Minister Peter MacKay told reporters Thursday that Canada and the U.S. are in agreement on the F-35 fighter jet. (Pawel Dwulit/Canadian Press)

A reversal of Canada's decision to purchase F-35 joint strike fighter jets would put the Canadian Forces at risk, Defence Minister Peter MacKay said Thursday.

"We need this aircraft," MacKay said at a joint press conference with U.S. Defence Secretary Robert Gates in Ottawa. "It is the only fifth-generation aircraft that has the capability and the on-board equipment and the stealth capacity and the weapons radar system that is interoperable with our colleagues and our allies in the United States through NORAD.

"The Liberal opposition is playing political games with this issue and that is a risk for the Canadian Forces."

The government announced it will spend $9 billion on a fleet of F-35 Lightning II Joint Strike Fighter jets in July, sparking an outcry from the opposition, who questioned the decision to sole-source the contract to Lockheed Martin.

Asked specifically about the Liberal Party's objection to the sole-source contract, Gates said he didn't want to get involved in domestic affairs but "my hope is, for all of our sakes, our partners continue to move forward with us on this program."

Afghan mission

MacKay and Gates also discussed the ongoing mission in Afghanistan, with Gates praising Canada's contribution, and offering sympathy and thanks to the families of Canadian soldiers killed.

"No country has suffered more fallen heroes proportionately more than has Canada," he said. "As Canadian forces begin transitioning from a combat role to one focused primarily on training the Afghan police and military, I am convinced they will be just as successful in this new capacity."

Canada's combat mission ends in July, though roughly 950 troops will take on a training role in Kabul after that.

It's expected that U.S. troops will replace the Canadians in Kandahar.

MacKay, asked whether Canada's training troops would remain in Kabul or could be moved to other regions at NATO's request, said the Canadian Forces "have looked at a few locations in the nearby regions... that are in close proximity to Kabul."

The bilateral meeting was originally intended to be trilateral; Mexican Defence Minister Guillermo Galván did not attend due to illness.