U.S. President Donald Trump's planned 25% tariffs on all steel and aluminum imports would be added onto other levies on Canadian goods, resulting in a total 50% tariff, a White House official said on Tuesday.

U.S. President Donald Trump said he will announce on Monday that the United States will impose 25 per cent tariffs on all steel and aluminum imports, including from Canada and Mexico — a move that prompted sharp criticism from some provincial premiers.

President Trump says he'll announce the U.S. will impose 25% tariffs on all steel and aluminum imports, including from Canada and Mexico, as well as other import duties.