Canadian Prime Minister Justin Trudeau launched a blistering response to President Donald Trump's decision to level punishing tariffs on his country. 

Looking directly into a TV camera and addressing 'Donald,' he said: 'Even though you are a very smart guy, this is a very dumb thing to do.'

Trudeau, at times close to tears during an emotional press conference in Ottawa, was quoting a previous verdict on Trump's tariff policy delivered by the Wall Street Journal.

U.S. Imports from Canada will now be taxed at 25 percent as Trump's tariffs went into effect on Tuesday. 

Trudeau said: 'Today the United States launched a trade war against Canada, their closest partner and ally, and their closest friend. At the same time they're talking about working positively with Russia, appeasing Vladimir Putin a lying murderous dictator. Make that make sense.'