US President Donald Trump announced on Monday that the US would double tariffs on Canadian vehicles from 2027 as he accused Ottawa of "ripping off the United States of America for years."

In a post on his Truth Social account, Trump wrote: "On January First, 2027, Tariffs on all Cars, Trucks, both large and small, Automotive Parts, and Steel, will be increased to 50%."

Current US tariff rates on automobiles stand at 25% for non-US content.

The threats come amid a growing trade war between the two neighbours that hit a flash point on Friday after talks over a deal to avoid 50% duties on some Canadian goods collapsed as both sides accused each other of trying to implement last-minute changes.

Canadian Prime Minister Mark Carney said Canada had been forced to walk away from the "bad" deal as "we cannot accept what they've offered, and we will not give what they've asked."