"I really like him a lot," the president said of Canadian Prime Minister Mark Carney, as he addressed journalists aboard Air Force One. "But what they did was wrong."

So "no," discussions will not resume, Trump said in response to a reporter's question, even though Carney "apologized for what they did with the commercial because it was a false commercial."

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Trump reacted strongly to a Canadian anti-protectionist advertising campaign: after abruptly ending bilateral trade talks, he then imposed an additional 10% increase in tariffs on Canadian products.

The Republican nevertheless reiterated that he had a "good relationship" with Carney and that they had had a positive discussion on the sidelines of the APEC summit in South Korea.

A few days earlier, at another summit in Malaysia, Carney had for his part repeated that Canada was ready to resume trade negotiations with Washington.

The breakdown of talks represents a sudden reversal in relations between two historic allies that have been shaken by Trump's return to power.

Canada is the US' second-largest trading partner and a major supplier of steel and aluminum to US companies.

The vast majority of cross-border trade remains exempt from tariffs due to the North American Free Trade Agreement, but sectoral levies – particularly on steel, aluminum, and automobiles – have hit Canada hard, forcing job losses and squeezing businesses.