WASHINGTON—The U.S. will impose tariffs on steel and aluminum imports from Canada, Mexico and the European Union starting on Friday, the Trump administration said, raising the specter of trade war with some of Washington’s closest allies, who said they would retaliate.
Canadian Prime Minister Justin Trudeau on Thursday said Ottawa will impose billions of dollars of tariffs on steel, aluminum and a wide range of other U.S. goods, including some food and agricultural products. Canada said it would hold consultations for two...