Both President Donald Trump and Prime Minister Mark Carney have poured cold water on the idea they will reach a quick, and tariff-free, deal. And Trump's open criticism of Canada's move to recognise a Palestinian state dashed hopes for a last minute agreement earlier this week.

Trump has justified tariffs on goods from Canada, the top U.S. export market, by accusing it of failing to stop the cross-border flow of fentanyl, even though U.S. government data shows Canada accounts for only 1% of the fentanyl that enters the United States.

After Canada failed to strike a trade deal with Washington, the president raised tariffs on some Canadian exports this week.