President-elect Donald Trump said Monday that his incoming administration would slap new tariffs on imported goods from Mexico, Canada and China, solidifying a key campaign promise that could have a major impact on trade.

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.

The tariffs, if implemented, could dramatically raise prices for American consumers on everything from gas to automobiles to agricultural products.