Canadian Prime Minister Justin Trudeau launches a stunning attack on Donald Trump's "dumb" trade war, sparking further threats of retaliation from the US president after huge tariffs kicked in against Canada, Mexico and China. A furious Trudeau accuses Trump of trying to cause the collapse of Canada's economy to make it easier for the United States to annex his country, and blasts Washington for targeting a close ally while "appeasing" Russia over Ukraine. IMAGES AND SOUNDBITES