(CNN)The head of the International Olympic Committee (IOC) has promised the organization will pursue a policy of "zero tolerance" if allegations of widespread doping by track and field athletes at the Olympics are proven.
Leaked doping files: IOC makes 'zero tolerance' pledge
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Allegations published in the Sunday Times and aired in a documentary by German broadcaster ARD, claim that a third of medals awarded in the Olympic Games and world championships between 2001 and 2012 were won by athletes who recorded suspicious doping tests.
The news organizations have based their reports on a leaked database, held by the International Association of Athletic Federations (IAAF), which holds the results of 12,000 blood tests on 5,000 athletes.
"At this time we've nothing more than allegations, and we have to respect the presumption of innocence," IOC president Thomas Bach told reporters. "If there should be cases involving results at Olympic Games, the IOC will act with zero tolerance with our usual policy."
The tests were scrutinized by Australian doping experts Michael Ashenden and Robin Parisotto, who concluded that 800 athletes, in a range of disciplines, mostly covering endurance events from the 800 meters to the marathon, had produced "suspicious" results.
At the major competitions, this equated to nearly 150 medalists, including 55 gold medal winners.
It is claimed no action has been taken against these athletes.
"Never have I seen such an alarmingly abnormal set of blood values," Parisotto told the Sunday Times.
While the results do not prove doping, they do raise serious questions for the IOC, the IAAF and the World Anti-Doping Agency (WADA).
"WADA is very disturbed by these new allegations that have been raised by ARD, which will, once again, shake the foundation of clean athletes worldwide," the agency's president, Craig Reedie, said in a statement on its official website Sunday.
"Given the nature of these allegations, which are an extension to those that were raised by ARD's December 2014 documentary, they will immediately be handed over to WADA's Independent Commission for further investigation," he added.
A previous ARD documentary, televised in December 2014, had placed the spotlight on the Russian track and field program, with claims of systematic doping and ineffective scrutiny by the IAAF. Those claims were strenuously denied by the Russian authorities.
WADA set up an Independent Commission, chaired by its founding president Dick Pound, to investigate the earlier allegations about the Russian program in response to ARD's earlier documentary.
The allegations implicated athletes, coaches, as well as the IAAF-accredited testing laboratory based in Moscow.
The commission is due to report by the end of the year, but Reedie has now extended its original remit.
"These allegations require swift and close scrutiny to determine whether there have in fact been breaches under the World Anti-Doping Code and, if so, what actions are required to be taken by WADA and/or other bodies.
"As always, WADA is committed to doing what's necessary to ensure a level playing field for clean athletes of the world," he said.
The new allegations -- which claim athletes are using blood transfusions and minute doses of EPO -- again implicate Russia -- reporting that 80% of its medal haul between 2001 and 2012 was claimed by athletes whose test results were cause for concern.
The Russian Olympic Committee and Russian Anti-Doping Agency was not immediately available for comment regarding the latest allegations.
Kenya, one of the leading countries in endurance running events, had won 18 medals won by suspicious athletes, the database reveals.
"The timing of the libelous report contained in almost half of the 55 minute documentary which alleges widespread systematic doping in Kenya is extremely suspect and ill motivated, coming on the day we selected our team for the IAAF World Championships," said a statement on the Athletics Kenya website.
"In our continued fight against doping we have sanctioned a number of athletes found to be in violation and the information is in the public arena. This is besides ordering all our sanctioned events, not only at national but also regional (grassroots) level to have doping control as mandatory requirement."
The IAAF responded to the allegations with a statement Sunday ahead of a "full detailed response", a spokesperson told CNN.
"The relevant allegations were broadcast on WDR (ARD) in Germany yesterday and have been repeated in an article in the Sunday Times newspaper today," it read.
"They are largely based on analysis of an IAAF data base of private and confidential medical data which has been obtained without consent.
The statement added that it "will reserve the right to take any follow up action necessary to protect the rights of the IAAF and its athletes."
The reports come as the IAAF is preparing to host its world championships in Beijing later this month from August 22-30.