US presidential hopeful Mitt Romney tried to put the fuss caused by his criticism of London's Olympic preparations behind him Friday, admitting that the British capital now seems ready for the games. The Republican challenger, who will face off against President Barack Obama in November's US election, offended many in Britain on Thursday when he began a visit to London by expressing concern about the host city's readiness. Britain's Prime Minister David Cameron slapped down the remarks and the mayor of London, Boris Johnson, fired up a 65,000-strong crowd gathered to welcome the Olympic torch by taunting the US visitor. The controversy overshadowed the first day of a three-nation foreign tour designed to showcase Romney as an international statesman and he quickly tried to backtrack on his comments -- without offering an apology. On Friday, speaking to US network NBC, Romney explained that he had been concerned about reports of the challenges facing Olympics organisers, adding: "But after being here a couple of days, it looks to me like London is ready." The partial climbdown came too late to save him from the mockery of the patriotic British press, and also of many members of the British public who took to social media sites to mock their American guest. And he also appeared to have embarrassed at least one countryman, US athletics legend Carl Lewis, who told British daily The Independent: "I swear, sometimes I think some Americans shouldn't leave the country." Romney, who organised the 2002 Winter Olympics in Salt Lake City, had said on Thursday reports of shortcomings in security for the London games and warnings of a possible strike by customs officers were "disconcerting". But the British leader Cameron responded with an apparent swipe at Romney's own record -- and at the US city itself -- saying: "Of course it's easier if you hold an Olympic Games in the middle of nowhere." When this was put to him, Romney said he hadn't interpreted Cameron's remarks as a rebuke, but conceded some ground. "Of course it is hard to put on games in a major metropolitan area and what they've done that I find so impressive is they took the venues and put them right in the city," he told NBC. "You're going to be able to be just in the backside of 10 Downing Street for beach volleyball for instance." Romney will attend Friday's opening ceremony of the games with his wife Ann, who has a horse taking part in the Olympics dressage event, before continuing on a tour if US allies that will take him to Poland and Israel.