In a rancorous speech the EU Commission chief accused the eurosceptic President of giving him the “cold shoulder” and ignoring the role of eurocrats in running European trade negotiations.
Mr Trump has openly stated previously that he prefers dealing bilaterally with countries on a one to one basis and is not a fan of overbearing supranational structures like the EU.
Donald Trump and Jean-Claude Juncker are at loggerheads over trade
He reportedly pressed Angela Merkel for a swift trade deal during her trip to the White House earlier this year, prompting a bemused response from the German chancellor who replied that all agreements had to go through Brussels.
The billionaire tycoon has also been publicly keen on striking an economic pact with Britain, which will be able to forge its own trade policy for the first time in 45 years once it has left the EU.
The US President wants to strike trade deals with individual European countries
Talking about Mr Trump’s attitude towards Europe, the EU chief said: “They say: ‘We do not want to negotiate with you as a European Union but with each member state separately’.
“We cannot allow individual [trade] agreements between the Americans and individual European countries to take place.”
Mr Juncker made his remarks about the US administration just hours after it emerged that it is likely to pull America out of the international Paris Agreement on climate change.
The Brussels boss said he had raised concerns about America’s apparent isolationism during Mr Trump's visit to Brussels last month, but that they fell on deaf ears.
And now reports have emerged that the EU will seek to realign itself with China on the issues of trade and climate change after becoming exasperated with the US President.
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Mr Juncker said: “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."
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Striking a pessimistic tone, he continued: “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 US to withdraw from international economic life. But he wants to do this. I’m against it, but he does not care at all.”
A vital bi-lateral summit between the EU and China, at which the two are set to strengthen ties, is taking place in Brussels today with ongoing commitment to the Paris Agreement expected to be top at the agenda.