US President Donald Trump has said he is immediately ending all trade negotiations with Canada.

In a post on Truth Social, Trump wrote that the country had run an advert featuring former US President Ronald Reagan speaking negatively about tariffs.

"Based on their egregious behaviour, ALL TRADE NEGOTIATIONS WITH CANADA ARE HEREBY TERMINATED," Trump wrote late on Thursday.

The US president has imposed a 35% levy on Canadian imports, although he has allowed exemptions for goods that fall under the USMCA - a free trade agreement with Mexico and Canada that Trump negotiated during his first term.

Trump said the video, sponsored by the Ontario government, was designed to "interfere with" the US Supreme Court, referring to an upcoming decision in November on whether Washington's sweeping global tariffs are legal.

The court's decision represents the biggest test of Trump's presidential authority and signature economic policy, potentially forcing the US to refund billions collected in tariffs.

In the minute-long advert published last week, Reagan's voice is heard narrating over images that include the New York Stock Exchange and cranes adorned with both US and Canadian flags.

The video excerpts a 1987 national radio address by Reagan that focused on foreign trade.

"When someone says 'let's impose tariffs on foreign imports', it looks like they're doing the patriotic thing by protecting American products and jobs. And sometimes, for a short while it works, but only for a short time," Reagan says.

"But over the long run, such trade barriers hurt every American, worker and consumer.

"High tariffs inevitably lead to retaliation by foreign countries and the triggering of fierce trade wars... Markets shrink and collapse, businesses and industries shut down and millions of people lose their jobs," Reagan adds.

In a post on X, the Ronald Reagan Foundation said that the Ontario government had used "selective audio and video" of the former US president's remarks on tariffs.

"The Government of Ontario did not seek nor receive permission to use and edit the remarks," the statement added.

The foundation said the advert "misrepresents" the former president's address, without specifying why.

It said the foundation is "reviewing its legal options".

In the post accompanying the video advert, Ontario Premier Doug Ford wrote that "we'll never stop making the case against American tariffs on Canada."

Ford, who leads Canada's most populous province and its largest economy, has been a vocal critic of the US tariffs.

Ontario has been among the Canadian provinces hardest hit by the US tariffs, particularly in the car and steel industries.

Ford hit back at Trump's earlier tariff threat against Canada by saying he was willing to cut off power supply to the US.

He had also described Washington's trade policies against Canada as having pulled a knife and "yanked it into us", and called on US lawmakers to put pressure on Trump.

Mark Carney and Doug Ford have not yet commented on Trump's announcement.

The advert was run as part of a campaign worth $75m Canadian dollars (£40m; $54m) on mainstream TV channels in the US.

Trump has also imposed sector-specific levies on Canadian goods, including 50% on metals and 25% on automobiles.

The White House's global tariffs - particularly on steel, aluminium and cars - have hit Canada hard, forcing job losses and putting pressure on businesses.

China's embassy in Washington also used a similar Reagan clip in a post on X to cast doubt on Trump's global tariffs earlier this year.