US stocks fell on Friday after President Donald Trump threatened a 35% tariff on Canada — a sharp escalation in an ongoing trade war.

President Donald Trump threatened a 35% tariff on some Canadian goods and raised the prospect of increasing levies on most other countries, ramping up his trade rhetoric in comments that weighed on stocks and boosted the US dollar.

Trump this spring imposed a 25% tariff on cars and car parts, including those from Canada. But certain cars and parts qualify for preferential treatment under the USMCA, meaning the 25% tariff applies only to the non-U.S. content of the automobile or part.