The president-elect’s threat to hit Canada, Mexico and China with new tariffs is already rocking business and diplomatic relationships and could topple the trade pacts he signed in his first term.

Senior Canadian figures have reacted with shock and concern to Donald Trump's announcement that he plans to impose tariffs of 25 percent on all goods entering the United States from Canada and Mexico when returned to the White House.

Trump's promise to impose a 25% tariff on all imports from Canada and Mexico mimics his old strategy of using tariff threats as a negotiating tool.