Italy's foreign minister warned that, while he hopes for successful negotiations, the EU will respond resolutely to Trump's latest tariff threat.

Global markets were skittish on Monday after President Donald Trump threatened new 30% tariffs on imports from the EU and Mexico as of August 1. Although investors by now are accustomed to tariff talk,

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,