Donald Trump’s proposed 30% tariff on European Union goods is “effectively prohibitive” to transatlantic trade and could warrant retaliation, the bloc’s chief negotiator said.

The European Union and South Korea said on Monday they were working on trade deals with U.S. President Donald Trump that would soften the blow from looming tariffs as Washington threatens to impose hefty duties from August 1.

Announced US tariffs of 30% on imports from the European Union would severely impact trans-Atlantic trade and supply chains, the EU's lead trade negotiator warns. "There will be a huge impact on trade.