The Sun said the interview was conducted Thursday in Brussels, before Trump traveled to Britain.
The long-awaited document proposes keeping Britain and the European Union in a free market for goods, with a more distant relationship for services. He also praised one of May's political rivals, former foreign secretary Boris Johnson. The U.S. can not negotiate a trade deal with the United Kingdom until that date Theresa May cited, which is in 2019.
He also noted that many Americans based in London joined the protests against Mr Trump. May, who was already reeling from a backlash within her Conservative Party caucus over a new Brexit plan she announced last week that included a customs arrangement with the EU. "She wanted to go a different route", Trump said, adding that May "didn't listen".
He added: "I'm not quite sure whether this will be enough of a proposal".
President Donald Trump pulled off a diplomatic backflip on Friday, reversing himself on trade, Brexit and his critical assessment of British PM Theresa May while insisting the US-UK relationship is "the highest level of special".
Sadiq Khan has said he will not rise to Donald Trump's "beastly" comments, as he urged Theresa May to stand up to the US President.
34-year-old Eric flew into Aberdeen Airport on a Trump plane earlier today, with his father flying into the United Kingdom around lunchtime ahead of a meeting with the Prime Minister and the Queen.
"I was very saddened to see he was leaving government and I hope he goes back in at some point", Trump said.
Trump said: "I think he has not been hospitable to a government that is very important".
Trump is now involved in serious discussions about redesigning the presidential aircraft, which would include a new red, white and blue design, according to multiple reports. Barriers where they won't take our farm products, they won't take many of our things, including our cars. "I don't take questions from CNN", Trump told Acosta, who's network he has long had a beef with. "But when they make you feel unwelcome, why would I stay there?" he asked. Brits gathered outside the United States ambassador's residence in London, where the Trumps are staying, according to reports.
Mr Khan was speaking as Labour MP David Lammy accused Mr Trump of being a "racist" who "hates that London chose a Muslim mayor".
"I think he has done a bad job on crime, if you look, all of the frightful things going on there, with all of the crime that is being brought in", he said.
Speaking to the Sun, Mr Trump attacked Mr Khan over the wave of terrorist attacks in London past year and accused him of doing "a bad job".
"I love the United States but I love getting along with Russian Federation and China and other countries". "But it is too bad what is going on", he said.