Canada’s conservative Government said on Tuesday it was investigating the leak of a memo that suggested US presidential hopeful Barack Obama’s harsh words about the North American Free Trade Agreement (NAFTA) were for political show.

The 1,300-word memo, circulated within the Canadian Government, had said Obama’s senior economic adviser, Austan Goolsbee, told Canadian officials in Chicago that the debate over free trade in the Democratic presidential primary campaign was “political positioning”.

Goolsbee said his comments were misinterpreted, and Obama denied offering the Canadians any such ideas. “Nobody reached out to the Canadians to try to assure them of anything,” Obama told reporters Monday in Carrollton, Texas.

Canadian Prime Minister Stephen Harper on Tuesday called the memo’s leak “completely unacceptable”, and vowed his Government would find out who was responsible.

“The Canadian Embassy in Washington expressed it’s apologies regarding the leaking of this information,” Harper said in Parliament. “

“The government is trying to find who’s responsible for this information being made public.”