During the interview with The Sun ahead of his visit to the UK, Trump said May ignored his advice by taking a soft stance on trade with the European Union as the UK exits and said that decision would "kill" any chance of an effective trade deal with the U.S.
London regards its "special relationship" with the United States as a keystone of foreign policy and May has courted Trump ahead of Britain's departure from the European Union. "I actually told Theresa May how to do it, but she didn't listen to me". "She wanted to go a different route", he told the paper.
Mr Khan said the Prime Minister should not be afraid to challenge the Republican property mogul, who also provoked anger by criticising her Brexit plans and praising her rival, Boris Johnson, as having the ability to be a "great prime minister".
Addressing the row at a joint news conference with Mrs May on Friday, Mr Trump claimed he "didn't criticise" Mrs May and has a "lot of respect" for her.
"She said: 'Don't worry it's only the press.' I thought that was very professional". "I was very saddened to see he was leaving government, and I hope he goes back in at some point".
This is what White House spokespeople do when a statement they're tasked to deliver is ridiculous and they'd rather attribute it to Trump rather than sacrifice their own credibility.
The Sun's write-up of its interview, which was recorded, quoted him describing her as a "nice person" and saying they get along "very nicely". "He thought she was great on North Atlantic Treaty Organisation today and is a really terrific person. He is thankful for the wonderful welcome from the Prime Minister here in the U.K".
Trump first met May Thursday night and the pair spoke for about 90 minutes and attended a state dinner.
He said Mr Trump's remarks on trade were a "perfectly reasonable thing for an American president to say". Friday, the two held more talks on more issues.
The press conference kicked off with the PM telling reporters from the United Kingdom and USA that a trade deal between the two countries would be discussed after Brexit.
With protests expected to continue well into the evening (and with the orange-hued baby Trump still flying high over central London), take a look at some of the best signs yet.
Arriving straight from a North Atlantic Treaty Organisation summit that was predictably contentious, the USA president has been greeted with massive protests on his first trip to London since taking office.
Shadow equalities secretary Dawn Butler said: "Donald Trump's comments about Sadiq Khan are as offensive as they are wrong".
Donald Trump may face more protests this weekend as he winds down from his working visit with a round or two on his private golf course.
"He's really quite stung by the criticism he's been getting", Dunn said.
While one annoyed user said: "This reminds us of that time Trump landed in Scotland and congratulated them on Brexit when 62 percent of Scotland voted Remain".