The European Union has warned that its trade with the United States could be effectively wiped out if Washington makes good on its threat to slap a 30% tariff on goods imported from the bloc.

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

Stocks closed slightly higher on Monday, shrugging off President Donald Trump's announced tariffs over the weekend targeting the European Union and Mexico. Those new levies rekindled tensions with two of the largest U.S. trade partners and threatened to raise consumer prices.