The Chinese authorities last night came under fire from the United States government for their lack of tolerance after an American gold medallist was banned from visiting Beijing for the Olympic Games, which open tomorrow.

The White House press secretary, Dana Perino, said the US would complain after Joey Cheek, a speedskater who won gold in Salt Lake City in 2002, was informed yesterday morning that his visa had been revoked, hours before he was due to travel. Cheek is a co-founder of Team Darfur, which has encouraged 73 athletes to use the platform provided by the Olympics to protest at China's support for the Sudanese government, which is accused of sponsoring genocide in the region.

"I didn't see it coming," said Cheek. "I figured once they gave me a visa, I wouldn't imagine they wouldn't allow me to come in later. That was a big shock. I wasn't expecting to get a call the evening before I was leaving for Beijing. I don't begrudge them the Olympics, I think they'll do well with them, but there are so many of their government's policies that I find repulsive, especially for athletes who have no intention but to help someone else."

The decision by a host city to stop an Olympic champion attending the Games is highly unusual, but the International Olympic Committee notably failed to censure China or offer any support for Cheek yesterday. Giselle Davies, the IOC's spokeswoman, said: "The Olympic Games are about the athletes, the active athletes that are competing. Joey Cheek had no formal role and is not accredited in any capacity, so in that sense he is a normal citizen who requires a visa like any other. As such this is really a matter for the Chinese government to respond to, not the IOC."

Earlier in the day four US cyclists apologised to the Beijing organising committee after arriving in the city on Tuesday wearing masks. The athletes' statement was acutely embarrassing to the Chinese as they have been at pains all week to stress the absence of any threat to public health from pollution.

The US Olympic Committee's chief executive, Jim Scherr, said the four cyclists had been "overly cautious", but confirmed that the masks had been issued by his officials to around a third of the team.

President Bush angered Beijing by hosting five Chinese dissidents at the White House last week and his presence here this weekend is hugely sensitive. Bush, who criticised China's human rights record yesterday, is planning to cycle on the mountain bike course tomorrow before attending the opening ceremony.

The Beijing organising committee attempted to divert attention from the controversies by revealing its plans for the launch of the Games at the Bird's Nest stadium. More than 15,000 performers, 5,000 of them drawn from the military, will take part in a three-and-a-half hour ceremony that organisers promise will steer clear of references to recent Chinese history and focus instead on "the best of modern China" and cultural aspects of the country. Among the performers will be the British singer Sarah Brightman, who will sing the official Beijing anthem for the first time.

The 313-strong British team will be led into the stadium by the swimmer Mark Foster, who is competing in his fifth Games. Foster, the first swimmer since Anita Lonsborough to carry the flag, was selected for the honour by his fellow athletes, who for the first time voted for who they would like to head the team.