SYDNEY (AP) -- China has proven its commitment to cracking down on drug cheats by withdrawing more than two dozen Olympic athletes who failed doping tests, the White House drug chief said Wednesday.

 "It's a tremendous demonstration of their seriousness of purpose of acting against doping in their own teams," Barry McCaffrey said shortly after his arrival in Sydney. "It's a terrific signal that they are committed."

 McCaffrey said he sent a letter to China's sports minister congratulating him on the decision to drop 27 athletes and 13 officials from the Sydney Olympic team following a round of pre-games blood tests.

 "Some view these busts as a scandal," he said. "In our view, it's exactly the right signal that the Chinese and the international community mean business."

 After a week of saying that injuries, illness and poor performance were involved in some cases, Chinese officials said Tuesday that nearly all of the 27 athletes cut from the Olympic team failed drug tests.

 He Huixian, the Chinese Olympic Committee's spokeswoman, said "the overwhelming majority" had suspicious results in blood tests for the performance-enhancing drug EPO.

 Among them were six runners trained by famed coach Ma Junren, whose record-smashing "Ma's Army" stunned the world in the 1990s.

 Chinese sports have been riddled with drug scandals in recent years, but none involving so many people in one series of tests. In addition to the athletes, the Chinese cut 13 coaches, including Ma, from their squad.

 McCaffrey, who met with anti-doping officials in Beijing this year, said he will have more talks with the Chinese during his stay in Sydney.

 McCaffrey had been a strident critic of the International Olympic Committee and its anti-doping policies. But he said Wednesday that important progress has been made in the past 18 months -- including creation of the World Anti-Doping Agency, implementation of more than 2,000 unannounced out-of-competition controls worldwide and approval of a test for the banned endurance-boosting hormone EPO.

 "Clearly this is the beginning of a new era," McCaffrey said. "The Sydney Olympics will be the most drug-tested games in the history of sports."

 "There is a lot to be proud of," he added. "Having said that, we are probably a third of where we need to be."