July 12 (UPI) -- President Donald Trump arrived in London Thursday afternoon, where he will attend a state dinner and meet with British Prime Minister Theresa May -- after making his mark on the NATO summit in Belgium.
On arrival in London, Trump and first lady Melania Trump headed for Winfield House, the residence of U.S. Ambassador to Britain Woody Johnson, where the Beatles song We Can Work It Out played outside.
Trump left Brussels shortly after speaking to reporters and boarded Air Force One for the trip to London, where he will attend a state dinner Thursday night. He is scheduled to meet May and then Queen Elizabeth II before leaving Friday. He might also play a round of golf at his resort in Scotland.
Before leaving, Trump spent day two of the NATO summit renewing his call for member states to spend more -- this time up to 4 percent of their gross domestic product -- on defense. Trump had previously chastised under-spending members for failing to reach the 2 percent threshold required of all NATO allies by 2024.
The United States pays more than any other member on defense -- about 3.5 percent on NATO-related measures and 67 percent overall. All NATO members agreed in 2014 to mandate spending 2 percent of their gross domestic product on defense within 10 years, spending that effectively buys NATO protection.
At a news conference, Trump said the United States could withdraw from NATO and go it alone, if necessary, although he said that likely won't be needed. He also said he expects member states to boost their spending by next year.
"They will. I have no doubt about it," he said. "They all made commitments, and they will be up to 2 percent over a relatively short period.
"They have stepped up today like they have never stepped up before"
Earlier, Trump dictated his concerns on Twitter.
"Presidents have been trying unsuccessfully for years to get Germany and other rich NATO Nations to pay more toward their protection from Russia," one tweet said. "They pay only a fraction of their cost. The U.S. pays tens of Billions of Dollars too much to subsidize Europe, and loses Big on Trade!"
"On top of it all, Germany just started paying Russia, the country they want protection from, Billions of Dollars for their Energy needs coming out of a new pipeline from Russia," read another. "Not acceptable! All NATO Nations must meet their 2% commitment, and that must ultimately go to 4%!"
After taking a firm stance both days of the conference, which included calling Germany a "captive" of Russian energy, Trump did say U.S. commitment to NATO remains strong and he thanked other members for "additional money they are putting up." He later met with German Chancellor Angela Merkel to air his defense concerns.
U.S. allies played down Trump's suggestion he was responsible for increased defense spending.
Trump's calls prompted leaders to call an emergency meeting at the summit Thursday, which delayed a session during which NATO leaders had intended to discuss the Afghan conflict. On the issue, NATO Secretary-General Jens Stoltenberg has said he hopes to reach an agreement to fund Afghan security forces until 2024.
May has already committed 440 more troops to serve in non-combat roles in Afghanistan and the United States has committed 3,000.
Protests are also anticipated in Britain, where the Stand Up to Trump group prepared for a "Carnival of Resistance." Trump, though, will likely be gone from London before the demonstrations start Friday.
"We need to show the world what millions of people in this country think of the bigotry and the hatred that he represents," protest organizer Owen Jones said.
Trump will depart Britain Friday for Finland to prepare for a summit with Russian President Vladimir Putin Monday in Helsinki. Trump and Putin, who have never met for an official summit, will hold three sessions before the U.S. president returns to Washington, D.C., early Tuesday.