Manufacturers from Asia, Europe and elsewhere have poured billions into North American supply chains that could be hit by new taxes on Mexico, Canada and China.

US President Donald Trump has said he will follow through with his threat to hit imports from Canada and Mexico with 25% border taxes, known as tariffs, on 1 February. But he added that a decision about whether this would include oil from those countries has not yet been made.

TORONTO — Roughly $900 billion in annual trade between Canada and the United States — and, with it, traditionally chummy bilateral ties — is on the brink of upheaval, with President Donald Trump threatening to impose sweeping tariffs on Canada as early as this weekend.