Canadian Prime Minister Mark Carney said that he had apologised to United States President Donald Trump over a television advertisement that aired in the US featuring former president Ronald Reagan criticising tariffs.

The ad, which was paid for by the provincial government in Ontario, derailed negotiations between the US and Canada after Trump responded by halting trade talks and increasing tariffs on Canadian goods. He also claimed the advertisement was “fake” without providing evidence.

The clip included an excerpt from a 1987 radio address in which Reagan said that in the long term, tariffs “hurt every American worker and consumer” and trigger “fierce trade wars”. The address was edited, but there was no indication the excerpts were altered or taken out of context.

Speaking to reporters in South Korea, Carney said that Trump was “offended” by the ad and confirmed he and the US President spoke privately during a dinner earlier.

He said the decision to air the ad was “not something I would have done … and so I apologised to him”. He also noted his responsibility, “in my role as prime minister, for the relationship with the president of the United States”.

Carney also confirmed that he had reviewed the advertisement with Ontario Premier Doug Ford, a conservative populist and outspoken Trump critic whose government paid for the campaign, before it aired.

He said he told Ford of his opposition to the ad, saying: “It was time to speak, to discuss, to negotiate with the Americans”.

“Mr Ford has made a decision, he is independent, he can do it,” he continued, “but it’s not exactly useful.”

Ford, who later paused the campaign, wrote on social media that the ad “was intended to initiate a conversation about the impact of tariffs on American workers”.

British Columbia Premier David Eby said that his province plans to launch its own US advertisement against tariffs.

Trump said on Friday that Carney had apologised and spoke of his “very good relationship” with the Canadian Prime Minister but said trade talks between the two countries would not resume.

Carney said on Saturday that Canada is ready to restart trade negotiations when the US is ready to do so.

The relationship between Washington and Ottawa has grown increasingly strained since Trump returned to office in January, with the president imposing tariffs on Canadian goods and making repeated calls to make Canada the 51st US state.

Carney, a former central banker who won an election in April, campaigned as the best-placed candidate to handle Trump and manage the bilateral relationship between the countries.

He has repeatedly told the US leader Canada “is not for sale” but has walked back some of Canada’s retaliatory tariffs, and critics have accused him of capitulation.