U.S. President Donald Trump's new 25% tariffs on imports from Mexico and Canada took effect on Tuesday, along with a doubling of duties on Chinese goods to 20%, launching new trade conflicts with the top three U.

President Donald Trump delivered on his threat to hit Canada and Mexico with sweeping import levies, imposing one of the largest increases in US tariffs since the 1930s in a dramatic escalation of a trade war that stands to upend ties with major economic partners.

If President Trump's tariffs against Canada take effect, Canadian Prime Minister Justin Trudeau said the U.S. would immediately face a raft of countermeasures on Tuesday. Why it matters: Trump's comments Monday that he would impose 25% tariffs on Canada and Mexico sent markets sliding amid fears it could start a trade war,