The US imposed 50 per cent tariffs on some Canadian goods on Saturday after the two longstanding allies failed to reach a trade deal, with each side accusing the other of derailing days of talks.

The tariffs that came into effect just after midnight (0400 GMT) on some $20 billion of Canadian goods - things like wooden ice hockey sticks that are rarely used anymore - are far from an economic game-changer for the largest U.S. trading partner after Mexico. That represents just over 5 per cent of Canada's exports to the U.S.

But the new tariffs mark an increase in tensions between President Donald Trump and Prime Minister Mark Carney, and will likely make broader talks to renew the U.S.-Mexico-Canada free trade agreement more difficult.