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.

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.