President Donald Trump announced on Saturday that he is raising tariffs on Canada by an additional 10% above current levels.
The decision follows the airing of an advertisement sponsored by the Ontario government that featured clips from a 1987 speech by former President Ronald Reagan criticizing tariffs.
Trump described the ad as a fraudulent misrepresentation and a hostile act in a post on Truth Social.
He terminated trade talks with Canada on Thursday, citing the advertisement as the reason.
The ad, broadcast on major U.S. television networks, included Reagan stating that tariffs hurt every American worker and consumer and trigger fierce trade wars.
The Ronald Reagan Presidential Foundation & Institute stated that the ad misrepresented the former president's words.
Trump accused Canada of allowing the ad to run during World Series games despite promises to remove it immediately.
Ontario Premier Doug Ford announced on Friday that the campaign would pause on Monday to facilitate resumption of trade talks.
Canada is one of the United States' top trading partners, with $411.9 billion in goods imported last year.
Existing U.S. sectoral tariffs on autos, steel, aluminum, lumber, and energy have significantly affected Canadian exports.
Canada's unemployment rate has reached its highest level in nine years amid ongoing trade tensions.
Canadian Prime Minister Mark Carney indicated on Friday that Canada is prepared to resume negotiations with the United States.