The US president named the bloc – which includes some of his country’s oldest allies – as “a foe” ahead of Russia and China because of “what they do to us in trade”.
His comments, in a CBS interview filmed during his visit to the UK, emerged hours after Theresa May revealed the American leader had told her she should “should sue the EU” instead of negotiating the terms of Brexit.
During an interview at the president’s Turnberry golf club in Scotland, CBS News anchor Jeff Glor asked Mr Trump to identify his “biggest foe globally right now”.
The president replied: “Well, I think we have a lot of foes. I think the European Union is a foe, what they do to us in trade. Now, you wouldn’t think of the European Union, but they’re a foe.
“Russia is foe in certain respects. China is a foe economically, certainly they are a foe. But that doesn’t mean they are bad. It doesn’t mean anything. It means that they are competitive.”
Told that “a lot of people might be surprised to hear you list the EU as a foe before China and Russia”, Mr Trump responded: “Look, EU is very difficult... I mean my mother was Scotland, my father was Germany.
“And you know I love those countries. I respect the leaders of those countries. But, in a trade sense, they’ve really taken advantage of us and many of those countries are in Nato and they weren’t paying their bills.”
Speaking ahead of a meeting with Vladimir Putin on Monday, the US leader repeated a complaint – made during the Nato summit earlier this week – about a gas pipeline between Germany and Russia.
“They’re going to be paying Russia billions and billions of dollars a year for energy and I say that’s not good, that’s not fair,” he said. “You’re supposed to be fighting for someone and then that someone gives billions of dollars to the one you’re, you know, guarding against. I think it’s ridiculous.”
He accused Germany of “waving a white flag” to Moscow.
During the interview, Mr Trump also said he “hadn’t thought” about requesting the extradition of 12 Russian intelligence officers charged with hacking into Democrat emails in a bid to influence the 2016 election.
“I might. I hadn’t thought of that,” he told Mr Glor. “But certainly, I’ll be asking about it.”
The US does not have an extradition agreement with Russia.
Mr Trump will fly out of Scotland for a summit with the Russian president in Helsinki on Monday.
He leaves the UK following a whirlwind tour that included meetings with Theresa May and the Queen against a backdrop of mass protests against his policies.
The president broke diplomatic protocol by criticising Ms May’s approach to Brexit on the eve of his vist, saying in an interview with The Sun that she had ignored his advice.
In a bid to then repair relations during a joint press conference on Friday, he apologised for the interview and told reporters he had merely made a “suggestion” of what she might do.
Asked to set out exactly what the president’s advice was on BBC One’s Andrew Marr Show on Sunday morning, Ms May said: “He told me I should sue the EU – sue the EU – not go into negotiations, sue them.”
She added: “Actually no. We’re going into negotiations with them.”
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies