The head of the European Commission accused the U.S. administration on Wednesday of seeking bi-lateral trade deals with individual EU states, and said he would block any such attempt to break the bloc's unified position on trade.
European Commission President Jean-Claude Juncker said the Americans were adopting a "cold shoulder" towards the Commission, the EU executive body which negotiates trade on behalf of the whole bloc.
"They say: 'We do not want to negotiate with you as a European Union, but with each member state separately,'" Juncker said.
"We cannot allow individual (trade) agreements between the Americans and individual European countries to take place."
Juncker said he had told U.S. President Trump of his concerns about Washington's protectionist stance on trade.
"I don't think it's good that there is a picture evolving where, in the future, we would do more with China than with the United States," Juncker said.
"That's the wrong direction, I think. But I cannot prevent this from happening."
"We have explained to Mr Trump that it is not good for the U.S. to withdraw from international economic life. But he wants to do this. I'm against it, but he does not care at all."