President-elect Donald Trump on Monday promised massive hikes in tariffs on goods coming from Mexico, Canada and China starting on the first day of his administration, a policy that could sharply increase costs for American businesses and consumers.

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.

Trump, who takes office on Jan. 20, said he would impose a 25% tariff on imports from Canada and Mexico until they clamped down on drugs, particularly fentanyl, and migrants crossing the border, in a move that would appear to violate a free-trade deal.