Trump threatens trade war on Mexico, Canada, China

Donald Trump threatened to begin his presidency with a massive trade war -- and diplomatic crisis -- as he demanded China, Canada and Mexico stop illegal immigration and drug smuggling into the United States or face punitive US import tariffs.

In a series of posts on his Truth Social platform late Monday, the president-elect warned he would impose trade barriers on the top three US trading partners the day he takes office.

China quickly responded Tuesday that "no one will win a trade war," while Mexican President Claudia Sheinbaum said that tariffs were "not acceptable" and no way to address immigration and drug problems.

A Canadian government source said Prime Minister Justin Trudeau called Trump and had a "productive" discussion, without giving further detail.

Trump's posts signaled he intends to return immediately to the style of his first presidency, when he regularly shocked Washington and US partners around the world with major policy shifts announced at odd hours on social media.

If enacted, the tariffs would spark disruption across the global economy, deepening tensions with US rival China and upending relations with the two huge US neighbors.

However, the threat backs up one of Trump's main promises in his campaign against Democrat Kamala Harris, which was to use US economic muscle as leverage on issues having little to do with trade -- namely his claim that the United States is under siege by foreign crime and dangerous migrants.

"On January 20th, as one of my many first Executive Orders, I will sign all necessary documents to charge Mexico and Canada a 25 percent tariff on ALL products coming into the United States," Trump posted. "This Tariff will remain in effect until such time as Drugs, in particular Fentanyl, and all Illegal Aliens stop this Invasion of our Country!" he said. "We hereby demand that they use this power, and until such time that they do, it is time for them to pay a very big price!"

In another post, Trump said he would also be slapping China with a 10 percent tariff, "above any additional Tariffs," because the world's second biggest economy was failing to execute fentanyl smugglers.