"I think it is not proper to single Chinese swimmers out once they produce good results," said Jiang Zhixue, who heads the anti-doping agency of China's General Administration of Sport. "Some people are just biased."
His comments in China's official Xinhua news agency come after U.S. coach John Leonard said the performance of 16-year-old Chinese swimming sensation Ye Shiwen was "unbelievable" and "disturbing."
Ye won gold in the women's 400-meter individual medley Saturday with an unprecedented performance, shattering the previous world record by over a second. She swam the final 50-meter lap faster than American Ryan Lochte did in the men's race.
"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," Leonard told The Guardian on Monday.
He compared Ye's performance to that of Irish swimmer Michelle Smith, who tested positive for performance enhancing drugs following her victory in the same race during the 1996 Atlanta Olympics.
Jiang insists that the doping allegations are not justified, saying "Chinese athletes, including the swimmers, have taken nearly 100 drug tests since they arrived (in London)." He said the success was the result of an "advanced training method and hard work."
Chinese swimmers have in the past been tainted with high-profile doping scandals, most notably in the 1994 and 1998 world championships.
The International Olympic Committee's medical commission chief Arne Ljungqvist has said that no accusations should be brought against Ye unless it has been determined that she has tested positive for a banned substance.
Ye, who has denied taking performance enhancing drugs, races Tuesday in the final of the 200-meter individual medley.
Photo Gallery: Olympics Day 3
