Trump has also threatened to introduce tariffs - a tax on imports - on goods from Canada and Mexico, but paused these for 30 days after both countries agreed to boost border security. The US president has said tariffs are needed to help the American economy and to "protect" the country from the "major threat of illegal aliens and deadly drugs".

The initial market reaction was relatively mild. Future reactions may not be.

President Donald Trump has taken executive action to impose new tariffs on imports from Canada, China, and Mexico.

Donald Trump’s quest to reform the United States economy by implementing tariffs is moving quickly. The U.S. President had barely been back in the White House for a week when he started taking steps toward levying tariffs against Canada,

President Trump campaigned on using tariffs to revive domestic industry and fill America's coffers, but the tariff strategy now looks more muddled than ever. Why it matters: Trump has sent mixed signals about why his administration is slapping tariffs on billions of dollars' worth of imports,