U.S. futures and global stocks were hit by a selloff early on Monday as markets around the world braced for a potential trade war triggered by President Donald Trump’s decision to impose sweeping tariffs on imports from Canada, Mexico, and China—which he acknowledged will cause “some pain” for American consumers.

President Donald Trump said the U.S. pays hundreds of billions of dollars to "subsidize" Canada, and Canada can avoid tariffs by becoming the 51st state.