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 were mixed in early trading on Monday after President Donald Trump over the weekend issued 30% tariffs on the European Union and Mexico, rekindling tensions with two of the largest U.S. trade partners and threatening to raise consumer prices.