President Donald Trump continued to attack America's European allies on Thursday — this time aiming at the United Kingdom's Prime Minister Theresa May a day before they are due to meet in London.

British tabloid newspaper The Sun published an interview with Trump on Thursday, where the president blasted May's Brexit negotiations, as well as European immigration policy, NATO and London Mayor Sadiq Khan.

Trump said that May’s plan for a "soft Brexit" could scuttle an American trade deal with the U.K. because the island nation would remain too close with the European Union.

"We are cracking down right now on the European Union because they have not treated the United States fairly on trading," Trump said. "No, if they do that, I would say that would probably end a major trade relationship with the United States."

In the interview, Trump insisted that he would have negotiated the deal differently than May, and he said that he had provided the prime minister his "views on what she should do and how she should negotiate."

"I would have done it much differently. I actually told Theresa May how to do it but she didn’t agree, she didn’t listen to me. She wanted to go a different route," he said.

"I would actually say she probably went the opposite way," Trump said. "If you really look, she probably went the opposite way. And that’s fine. She should negotiate the best way she knows how. But it is too bad what’s going on."

But Trump declined to provide any details about the advice he provided May.

White House press secretary Sarah Sanders later issued a statement, saying Trump “likes and respects Prime Minister May very much."

She wrote: “As he said in his interview with the Sun she ‘is a very good person’ and he ‘never said anything bad about her.’ He thought she was great on NATO today and is a really terrific person."

The president also praised Boris Johnson, who just resigned as Britain's foreign secretary earlier this week because he did not approve of May’s negotiations over Brexit.

Trump even asserted that Johnson, a New York-born former mayor of London, "would be a great prime minister."

He said: "I think he’s a great representative for your country."

Trump also spoke on immigration policy in the interview, saying that Europe was losing its identity and culture because of an influx of migrants.

"Allowing the immigration to take place in Europe is a shame," Trump said. "I think it changed the fabric of Europe. And unless you act very quickly it’s never going to be what it was and I don’t mean that in a positive way. So I think allowing millions and millions of people to come in to Europe is very, very sad. I think you are losing your culture."

Trump conflated immigration and terrorism in the interview, and he said that Khan, London’s mayor, had done a "terrible job."

Trump also blasted Londoners in general, for protesting his arrival in England, and said that he "used to love London as a city," but added "when they make you feel unwelcome, why would I stay there?"

He did, however, praise the Queen Elizabeth II, whom he is scheduled to meet on Friday.

"If you think of it, for so many years she’s represented her country, she’s never really made a mistake," he said. "You don’t see, like, anything embarrassing. She’s just an incredible woman. My wife is a tremendous fan of hers. She’s got a great and beautiful grace about her."