President Donald Trump's new tariff orders against Canada, Mexico and China all contain clauses suspending a duty-free exemption for low-value shipments below $800 that is widely seen as a loophole that has allowed shipments of fentanyl and its precursor chemicals into the United States.

China's government on Sunday denounced the Trump administration's imposition of a long-threatened 10% tariff on Chinese imports while leaving the door open for talks with the U.S. that could avoid a deepening conflict.

President Trump moved to impose stiff tariffs on Mexico and Canada, whose leaders swiftly responded with their own levies, and accused Trump of starting a trade war that would debilitate all three economies.