U.S. President Donald Trump says he is adding a 10 per cent surcharge on imports from Canada, citing frustration over an Ontario government advertisement that criticized American trade tariffs. The ad, which used a quote from former U.S. president Ronald Reagan, aired during the opening game of the World Series and called for fairer treatment of Canadian products.

Trump announced the additional tariff on his social media platform Truth Social while en route to Malaysia aboard Air Force One. He said Ontario Premier Doug Ford should have removed the advertisement sooner, despite Ford’s commitment to take it down after the weekend.

The decision adds new tension to Canada–U.S. trade relations just as Prime Minister Mark Carney is in Asia promoting Canada as a stable, rules-based trading partner. Carney is attending regional meetings in Malaysia this week but has no formal meeting scheduled with Trump, according to the Prime Minister’s Office.

Economic experts say the new tariff could affect a wide range of Canadian exports, particularly in manufacturing and agriculture, though details on implementation have not yet been released by Washington.