United States President Donald Trump said on Friday that he is calling off trade negotiations with Canada in retaliation for taxes impacting major US tech firms, adding that Ottawa will learn of their tariff rate within a week.

“Based on this egregious tax, we are hereby terminating all discussions on trade with Canada, effective immediately,” Trump said in a post on his Truth Social platform.

He added that Canada will soon find out the levy it needs to pay to do business in the United States, calling his country’s northern neighbour “very difficult” to trade with.

Washington has previously taken issue with Canada’s digital services tax, requesting dispute settlement talks last year over the matter.

While Canada’s digital services tax is not new — it was enacted last year — US service providers are “on the hook for a multi-billion dollar payment in Canada” by June 30, noted the Computer and Communications Industry Association.

While Canada has been spared from some of Trump’s most sweeping duties, such as a 10 per cent rate imposed in early April on nearly all trading partners, it faces a separate tariff regime.

Since returning to the White House in January, Trump has also imposed steep levies on imports of steel, aluminium and autos.

Last week, Canada said it would adjust its 25pc counter tariffs on US steel and aluminium after Washington doubled its levies on imports of both metals to 50pc — if a trade deal was not reached within 30 days.