Chinese swimming sensation Ye Shiwen has firmly denied taking performance-enhancing drugs.
The 16-year-old was speaking at a press conference hours after adding the Olympic 200 metres individual medley title to the gold she won in the 400m version.
Critics expressed concern after she took five seconds off her personal best and more than a second off the world record in the 400m individual medley. But when asked tonight if she had used doping to improve her performance, she bluntly replied: "Absolutely not."
During the press conference, which was dominated by questions on the doping issue, she claimed the criticism was undeserved. She said: "I think this is a little bit unfair for me, however I was not affected by that. I'm not affected by the outside noise."
She agreed with the analysis of Jiang Zhixue, who leads anti-doping work at China's General Administration of Sport, who said the critics were biased. "I also feel the same way, they are biased," she said. "I think that in other countries other swimmers have won multiple golds and no-one has said anything. How come people criticise me just because I have multiple medals?"
American coach John Leonard described Ye's first gold medal performance as "disturbing" and "unbelievable".
But the Olympics' world body said drugs cheats at London 2012 would be caught and athletes who put in world record-breaking performances should be given the benefit of the doubt.
The International Olympics Committee (IOC) said critics concerned about Ye should "get real". "These are the world's best athletes competing at the very highest level," IOC communications director Mark Adams said. "We have seen all sorts of records broken already all over the place." And Mr Adams insisted London 2012 has "a very, very strong drug testing programme and we are very confident that, if there are cheats, we will catch them, as we already have done".
In a final, the first five athletes are tested compulsorily along with two others, the IOC said. It confirmed one athlete had been suspended and another handed a temporary suspension as a result of the testing programme in the run-up to the Games. Some 1,706 tests have been carried out so far, including 1,344 urine tests and 362 blood tests, the IOC added.
Ye's swim was described as "insanely fast" by previous world record holder Steph Rice - indeed, in the final 50m, Ye swam faster than the men's champion Ryan Lochte.