Without advance notice to Canada, the U.S. president put the auto industry into turmoil with a 25 percent tariff.

Canadian Prime Minister Mark Carney told President Donald Trump Friday that his nation will retaliate against the United States with tariffs of its own if Trump presses forward with his promised levies – potentially escalating what is already developing into an ugly and damaging trade war.

WASHINGTON—The Trump administration is scrambling to determine the specifics of its new tariff agenda ahead of its self-imposed deadline of Wednesday, weighing options as the president has promised to remake the American economy with a swath of new levies.

President Donald Trump expressed confidence that his tariff policy would prompt more Americans to buy cars made in the U.S.

Canada and Mexico won protections against potential new U.S. auto tariffs in 2018 as part of the U.S.-Mexico-Canada Agreement on trade, but there is no evidence that President Donald Trump will honor those commitments as he imposes 25% duties on global automotive imports.