The tariffs add a new front to a trade war largely driven by Donald Trump's announcement of tariffs on Canada, Mexico and China and threats of protectionist measures on other nations.

Beijing, which set steep duties on canola, peas and pork, wants Canada and Mexico to resist U.S. pressure to raise tariffs on Chinese goods.

President Donald Trump’s blanket 25% tariffs on Mexico and Canada took effect on Tuesday, an extraordinary action aimed at bringing America’s top trading partners to heel. But it threatens to weaken the North American economy,