President Donald Trump threatened a 35% tariff on some Canadian goods and raised the prospect of increasing levies on most other countries, ramping up his trade rhetoric in comments that weighed on stocks and boosted the US dollar.

The twists and turns in U.S. President Donald Trump's tariff policies have not only rattled global financial markets but have also taken investors on a roller-coaster ride. Adding to the uncertainty are tariff-related legal challenges and Trump's assertion that he would hammer out bilateral deals with trade partners.

President Donald Trump has launched a fresh assault on global trading partners with Canada likely to be among the worst hit.