Canada and China hit back swiftly after Trump's sweeping tariffs took effect Tuesday, raising fears of a global trade war. International markets, meanwhile, continued to slide.

"China will fight to the bitter end of any trade war," the foreign ministry spokesperson in Beijing declared, after China announced tit-for-tat tariffs on agricultural imports from the US. This came within minutes of a new 10% US levy on Chinese imports that came into effect on Tuesday - which adds to existing tariffs both from Trump's first term and those announced last month.