Donald Trump suggested on Sunday that the US could pull out of the World Trade Organisation and said that the EU had been created largely to compete against the US in international trade.
In an interview with NBC, the Republican presidential candidate said that the US might withdraw from the WTO if his plans to use tariffs to bring factories back from Mexico were challenged.
Mr Trump has made trade a central part of his populist economic message and has in the past threatened to pull out of the North American Free Trade Agreement and levy tariffs on Chinese goods. His comments on WTO appeared to take his anti-free trade rhetoric up a further notch.