US tariffs would stack for Canada, official says as countries condemn Trump moves

US President Donald Trump's planned 25 percent tariffs on steel and aluminum imports would pile on top of other levies on Canadian goods, resulting in a total 50 percent tariff if threatened duties on all imports from Canada are enacted in March, a White House official said on Tuesday.

Canada has not been told about the additive nature of the tariffs, a Canadian government source told Reuters, adding that it "sounds plausible."

Mexico, Canada and the European Union condemned Trump's metals tariffs on Tuesday and governments around the world braced for even more levies from the new administration amid fears of an escalating global trade war.

Businesses around the United States also warned of fallout, with many manufacturing-heavy companies finding it difficult to plan next steps or determine if Trump will follow through. The tariff hike would reverberate across the supply chain, affecting all businesses that rely on the materials, they said.