The advert, released by Ontario's government, features late US President Ronald Reagan warning that "trade barriers" hurt American workers

US President Donald Trump said on Thursday he was terminating trade talks with Canada, its largest trading partner, in response to an advertisement criticizing tariffs.

Trump imposed a 25% tariff on Canadian timber, steel, aluminum, and cars in the spring as part of a broader drive against what he called unfair trade practices, prompting Ottawa to retaliate. Talks on a new trade framework have been ongoing ever since.

Ontario, which has been hit hardest by the tariff hike as the US accounts for about 77% of its goods trade, last week released a social ad featuring a 1987 speech by President Ronald Reagan urging Americans to "reject protectionist legislation" and "promote fair and free competition."

"Over the long run... trade barriers hurt every American worker and consumer... High tariffs inevitably lead to retaliation by foreign countries and the triggering of fierce trade wars," Reagan says in the excerpt.d

In a post on Truth Social on Friday, Trump denounced the ad as "fake," accusing Canada of releasing it to influence US court hearings on the legality of his tariff hikes.

"Canada has fraudulently used an advertisement, which is FAKE, featuring Ronald Reagan speaking negatively about Tariffs," Trump wrote. "Based on their egregious behavior, all trade negotiations with Canada are hereby terminated."

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The Supreme Court will rule next month on whether Trump had the authority to impose the tariffs, after lower courts ruled against him. The duties remain in effect pending the decision.

Trump cited the Ronald Reagan Presidential Foundation and Institute, which first flagged the advert. The group said Ontario used Reagan's clips without permission and "misrepresented" his comments, threatening legal action, though in the full speech it posted, Reagan says exactly what appears in the ad.

Canada has yet to respond to Trump's announcement. Prime Minister Mark Carney said a day earlier that his government would block unfair US market access if further trade talks fail. The two are expected to meet next week at an economic summit in South Korea.