Hong Kong (CNN) -- Chinese swimmer Ye Shiwen has strongly denied that she's a drugs cheat following a series of record-breaking swims at the Olympics in the past few days.
"My achievements derive from diligence and hard work, I will never use drugs. Chinese athletes are clean," Ye told reporters late Monday. "The Chinese team is extremely strict on doping control, so I can assure you that is not an issue with us."
The 16-year-old world champion set a new Olympic pace for the 200-meter individual medley Monday with a time of 2:08.39 to take her into the Tuesday final -- which she won in another Games best time of 2:07.57 as she claimed her second title in London.
On Saturday, Ye smashed the world record to win gold in the 400-meter individual medley final, and stunned onlookers by logging a faster time in the last 50 meters than U.S. champion Ryan Lochte. Lochte won gold in the men's 400-meter individual medley the same night and is seen as one of the U.S.'s strongest contenders in the pool.
Over the last 50 meters of the 100-meter freestyle leg, Ye clocked a time of 28.93 seconds while Lochte swam his final 50 meters in 29.10 seconds.
Ye's impressive swim immediately raised suspicion that the teenager's world-beating results might be too good to be true.
However on Tuesday, British Olympic Association chairman Colin Moynihan sought to end speculation that Ye may have taken performance-enhancing drugs by confirming that the teenager had tested clean.
"She's been through (anti-doping agency) Wada's program and she's clean. That's the end of the story," he told reporters at a news conference.
On Monday, the head of the World Swimming Association, John Leonard, described her swim as "unbelievable" and suggested that there may be more to it.
"We want to be very careful about calling it doping," said Leonard, who is also the executive director of the USA Swimming Coaches Association.
"The one thing I will say is that history in our sport will tell you that every time we see something, and I will put quotation marks around this, 'unbelievable', history shows us that it turns out later on there was doping involved. That last 100 meters was reminiscent of some old East German swimmers, for people who have been around a while. It was reminiscent of the 400-meter individual medley by a young Irish woman in Atlanta," Leonard told the Guardian newspaper.
The young Irish woman in Atlanta he was referring to is Michelle Smith, now de Bruin, who won gold in three events at the 1996 Olympics only to receive a four-year ban two years later after being found guilty of tampering with a urine sample.
However, USA Swimming issued a statement distancing itself from Leonard.
"He is not an employee, representative or spokesperson for USA Swimming, nor is he a member of the U.S. Olympic Swim Team or a part of the official U.S. delegation here in London," it said Tuesday.
Jiang Zhixue, the anti-doping chief of China's General Administration of Sport, hit out at the allegations, saying they were unjustified.
"The Chinese athletes, including the swimmers, have underwent nearly 100 drug tests since they arrived here," he told Chinese state news agency Xinhua. "Many were also tested by the international federations and the British anti-doping agency. I can tell you that so far there was not a single positive case," he said.
In an interview with CNN, Xinhua's swimming correspondent Zhou Xin defended Ye's performance.
"It's not an unexpected victory. In fact, in the 400 medley Ye Shiwen just broke the world record and the faster result and now she continues in the 200 meters individual," she said.
Ye, who was born in the eastern Chinese city of Hangzhou, began swimming at the age of six after her teacher noticed she had large hands, which are considered to be an added advantage in the sport, according to Xinhua.
She joined the Zhejiang provincial swimming team in 2007 and the national team the year after.
From the age of 14, Ye scored a number of victories in national and international competitions.
On her Olympic profile, Ye's most memorable sporting achievement is listed as "winning the 200m and 400m individual medley at the 2010 Asian Games in Guangzhou."
She also won the 200-meter individual medley at the 2011 World Aquatic Championships in Shanghai.
Ye has attributed her success to her training schedule and hard work. "If the coach asks me to practice 10,000 meters, I would never be a lazy player to swim 9,900 meters instead," the Beijing Morning News quoted her as saying.
On Monday, former U.S. Olympic swimmer Mark Spitz, who won seven gold medals at the 1972 Munich Olympics, described Ye's swim on Saturday as "incredible."
"Normally people that break world records are sort of like fading at the end. Yet, she actually galloped ahead and caught up to the world record pace and passed it. ... It was an incredible finish. I've never seen anything like that in my life," he said.
Regarding allegations that Ye may have at some point used performance-enhancing drugs, Spitz said: "I wouldn't want to cast anything that would be negative toward her performance. It stands on its own unless she doesn't pass the drug test, which hasn't been proved yet."
The controversy over whether Ye used drugs started on Saturday when, during the BBC coverage of the race, presenter Clare Balding turned to her co-presenter, former British Olympian Mark Foster, and asked: "How many questions will be there, Mark, about someone who can suddenly swim much faster than she has ever swum before?"
The question provoked a backlash on social media in both the UK and China. On China's Twitter-like site Sina Weibo, one user wrote: "Those foreigners are all jealous, if the result shows no doping, you have to apologize." Another said: "You British won't be able to get gold medal even if you are on drugs."
Australian Stephanie Rice, the defending 200-meter individual medley champion who finished fifth in the Monday semi-final, said of her competitor: "She's a great 400 swimmer, she comes home like a gun in that freestyle."
Rice held the previous record for the 400-meter individual medley, but the Australian did it at the Beijing Olympics in 2008 with the aid of a polyurethane suit, which is now banned.
Ye also earned praise from Lochte. The 27-year-old American champion said Sunday, "It was pretty impressive. And it was a female. She's fast. If she was there with me, I don't know, she might have beat me."
CNN's Hilary Whiteman and Judy Kwon contributed to this report.