Republican presidential candidate Mitt Romney is visiting Britain's leaders, with the Olympics Games as a backdrop, as he seeks to send a message that he recognises the close bonds between the US and its top ally.

"We have a very special relationship between the United States and Great Britain,'' Romney told NBC News in an interview in London on Thursday.

"It goes back to our very beginnings - cultural and historical."

His overseas trip will also take him to Israel and Poland.

Romney's first official appearance during a campaign swing intended to highlight longtime US alliances was with David Cameron, the British prime minister.

He also met Tony Blair, the former prime minister, Nick Clegg, the deputy prime minister, and Ed Miliband, the leader of the opposition Labour Party.

Romney, a former private equity executive whose decades in private business gave him ample exposure to international affairs, is a former one-term governor of the state of Massachusetts untested on the world's political stage.

Fund raising

To that end, he hopes to persuade voters back home that he is no novice on foreign affairs and that they should elect him as president in a complex, dangerous world.

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Romney will spend part of his time in London raising money and highlighting a key part of his resume - the successful Salt Lake City Olympics he managed - with an appearance on Friday at the opening ceremonies of the London Games.

The meetings come a day after the Daily Telegraph newspaper published a story quoting an unidentified Romney campaign adviser saying the Republican believes the US relationship with Britain is special because of shared "Anglo-Saxon heritage" and that the White House does not appreciate that shared history.

Romney, however, quickly distanced himself from any such view.

"I don't agree with whoever that adviser might be, but do agree that we have a very common bond between ourselves and Great Britain," Romney told NBC News.

Nonetheless, Joe Biden, the US vice-president, and top Obama aides criticised Romney.

"The comments reported this morning are a disturbing start to a trip designed to demonstrate Governor Romney's readiness to represent the United States on the world's stage," Biden said.

Later on Thursday, Romney planned to hold a high-dollar fundraiser at the Mandarin Oriental hotel in London's Knightsbridge district.

One of the hosts of that fundraiser, former Barclays CEO Ian Diamond, withdrew from the event after he resigned in the wake of a rate-rigging scandal rocking British banks.