Donald Trump apologised to Theresa May for a newspaper interview in which he criticised her handling of the negotiations to leave Europe, using a press conference to lavish praise on the British leader as tough and determined.
"I have a lot of respect for the prime minister," he said. "I've been watching her over the last couple of days. She's a tough negotiator. She's a very very smart and determined person."
"I would much rather have her as my friend than my enemy."
He claimed that Mrs May brushed of the controversy by deriding the media coverage. "Don't worry, it's only the press," he quoted her as saying.
The pair held an outwardly convivial press conference on the lawns of Chequers, the country home of British prime ministers, at the end of several hours of talks. Mr Trump and his wife Melania then flew by helicopter to Windsor Castle when the president reviewed an honour guard from the Coldstream Guards before taking afternoon tea with Queen Elizabeth. The US president appeared visibly awed by the pomp and circumstance accorded to him and his wife.
During the press conference, Mrs May was adamant that Britain would be in a position to sign trade deals with the US when it left the European Union next year. The US leader said in the interview her negotiating stance had "killed" the prospect.
"Turning to our economic co-operation, with mutual investment between us already over $1 trillion, we want to go further," she said. "We agreed today, that as the UK leaves the European Union, we will pursue an ambitious US-UK Free Trade Agreement.
Trump in Britain
"A deal that builds on the UK’s independent trade policy; reducing tariffs, delivering a gold-standard in financial services co-operation, and - as two of the world’s most advanced economies - seizing the opportunity of new technology."
Mr Trump said after speaking to Mrs May's officials that a free trade agreement would still be possible, adding America wanted "full self-government" as it negotiates an exit from the European Union.
"We will see how that goes," he added.
Mr Trump sees the EU as a trade predator on the US and also warned that immigration has been "very bad" for Europe and is changing the culture of the continent. He even linked the policy to terror attacks on the continent.
"You see the same terror attacks that I do," he said. "I think it's changing the culture, I think it's a negative thing for Europe, a very negative thing."
Asked about Monday's meeting with President Vladimir Putin, Mr Trump said a poor relationship with Moscow was one of the "very bad hands" he had been left by President Barack Obama.
Tens of thousands of protesters gathered in central London to make their feelings about Mr Trump known. A giant inflatable baby blimp was tethered in front of parliament after the stunt gained approval from the London mayor, Sadiq Khan.
Mr Khan called on Mr Trump to explain why he keeps singling out him out for criticism.
London's first Muslim mayor said Friday that many major cities, including Paris, Brussels and Berlin, have suffered terrorism attacks but that Trump has chosen to only criticise him.
The mayor challenged Trump's claim that Europe is "losing its culture" because of immigration. Khan says immigration has brought "huge" social, economic and cultural benefits to London and to Britain.
Meanwhile Melania Trump visited the Royal Hospital Chelsea, a historic London retirement home for hundreds of former British soldiers.
Mrs Trump split off from her husband Friday morning for the solo outing to the hospital, which dates from over 300 years ago to the reign of King Charles II.
The first lady was accompanied by Mrs May's husband, Philip.
She met local schoolchildren and mingled with the hospital's resident veterans, known as Chelsea Pensioners.
As European leaders digest Mr Trump's comments at Nato and in London, the French foreign minister accused the US president of trying to "destabilise" the EU.
French Foreign Minister Jean-Yves Le Drian said Friday on BFM television that Trump "can't tolerate that there is an ensemble called the European Union". But, he added, "Europe will not let itself be destabilised."