All three Detroit automakers, along with others, build vehicles in Canada and Mexico that will face tariffs imposed by Trump.

Higher prices will deter buyers and force automakers to curtail production, said Jonathan Smoke, chief economist at Cox Automotive. He forecast that U.S. factories would produce 20,000 fewer cars per week, about 30 percent less than usual.

President Donald Trump's tariffs on auto imports will deal a heavy blow to European carmakers, especially German manufacturers, which rely on the US markets for a big chunk of their profits.