Canada was scrambling Tuesday to blunt the impact of US President-elect Donald Trump's threat to implement steep tariffs once he takes office, as experts warned of a potentially "catastrophic" hit to the Canadian economy.

The president-elect said that he would impose the across-the-board tariffs on Day 1 and that they would stay in place until Canada, Mexico and China halted the flow of drugs and migrants.

President-elect Donald Trump said he would impose the import tariffs — 25 percent for Canada and Mexico and 10 percent for China — as soon as he takes office.