Bach said it is up to the World Anti-Doping Agency to investigate the allegations, including that one-third of medals in endurance races at the Olympics and world championships from 2001 to 2012 were won by athletes who recorded suspicious blood tests.

"If there should be cases involving results at Olympic Games, the IOC will react with zero tolerance with our usual policy," Bach said.

German broadcaster ARD and The Sunday Times newspaper in Britain said they obtained access to the results of 12,000 blood tests involving 5,000 athletes. The leaked files came from the database of the International Association of Athletics Federations.

The report found that 146 medals — including 55 golds — in disciplines ranging from the 800 meters to the marathon at the Olympics and world championships were won by athletes who have recorded suspicious tests. The Sunday Times said that 10 medals at the 2012 London Olympics were won by athletes with suspicious results, and that in some finals every athlete in the medal positions had recorded a dubious blood test.

The International Olympic Committee has previously stripped medals from athletes who have been retroactively found guilty of doping offenses dating back to the time of the games. The IOC also stores Olympic doping samples for 10 years for possible retesting.

"We have full confidence in the inquiry by WADA," Bach said. "If needed, we will follow suit ... and do everything to protect clean athletes." On a separate issue, Bach said water pollution will be among the topics for discussion when he travels to Rio de Janeiro for Wednesday's one-year countdown to the 2016 Olympics.

An Associated Press investigation published last week revealed high counts of disease-causing viruses in the sewage-polluted waters where some Olympic competitions will take place. The IOC has since been advised by the World Health Organization that testing should be expanded to include viruses, not just bacteria.

Bach discussed the doping allegations on Monday with WADA chief Craig Reedie. The IAAF and WADA were already investigating accusations made in two previous ARD documentaries of alleged systematic doping and cover-ups in Russia.

The latest ARD program, called "Doping Top Secret: The Shadowy World of Athletics," was broadcast three weeks before the world championships in Beijing, which run from Aug. 22-30.

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