Beijing | Exporters from China, Canada and Mexico are seeking to front-load shipments to the US after president-elect Donald Trump pledged to impose new levies on goods from the three countries on his first day in office.

Mexico has supplanted China as the main source of goods, but imports keep climbing.

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.

Economists worry that Trump's tariff plan will raise the prices of a range of imported goods, from cars to electronics.

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

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.