Global investors got a harsh reminder of the risks around trade tariffs and U.S. President Donald Trump's deal-making on Saturday after he threatened fresh tariffs on his biggest trading partners in Europe and Mexico.

President Trump on Thursday threatened to impose a 35% tariff on Canadian goods beginning Aug. 1. Mr. Trump's latest salvo came after he also threatened tariffs on a number of other countries earlier in the week,

European leaders sound off on the 30% tariffs U.S. President Donald Trump threatened to impose on the trade bloc.