These allegations - strongly denied by Russia’s Athletics Federation - were first aired last December in a series of documentaries broadcast by German broadcaster ARD.

New allegations arising from the leak of International Association of Athletics Federations (IAAF) data showing the results of 12,359 blood tests given by more than 5,000 athletes over an 11-year period starting in 2001 have now been made by the same TV station and the Sunday Times in London.

More than 800 athletes had given blood samples that were "highly suggestive" of doping or "abnormal", it was reported, with a third of medals in endurance events at the Olympics and World Championships over the period, consisting of 55 golds at events including the London 2012 Olympic Games, won by athletes who submitted such samples.

It is understood that the need to assess these new allegations may push back completion of the report, which is not due to be handed to WADA President Sir Craig Reedie until December 31, but which Sir Craig himself told the International Olympic Committee (IOC) Session on Saturday (August 1) that he expected to receive in the autumn.

A delivery date closer to the deadline now looks more likely.

There is even provision in the Commission’s terms of reference for the deadline to be extended if Sir Craig "deems it appropriate".

The report would then normally be published in full within 30 days of delivery.

This emerged as IOC President Thomas Bach told journalists at the conclusion of the 128th IOC Session in Malaysia that the body would act with "zero tolerance" if investigations resulted in doping sanctions being imposed on athletes on the basis of samples taken at the Olympic Games.

Bach said: "I don’t know about the detailed allegations - which athletes, which competitions are affected.

"I had a conversation with the WADA President this morning.

"We agreed WADA is our competent centre for the fight against doping.

"They will inquire [into] these allegations.

"If there should be cases involving results at the Olympic Games, the IOC will act with zero tolerance.

"But at this time we have nothing more than allegations and we have to respect the presumption of innocence for the athletes.

"We are looking forward to receiving the report by WADA."

The issue was raised during this morning’s Session proceedings by Adam Pengilly, an IOC member from the United Kingdom.

Pengilly criticised the IAAF who he said "seem to have been quite silent over the last year about these allegations".

He hoped that the new President - either Sergey Bubka or Sebastian Coe - would "prioritise" the problem.

This sparked a reaction from current IAAF President Lamine Diack, who defended the body he has overseen since 1999, claiming: "We have always shown how strong we are".

Diack promised the governing body would look at the allegations and redistribute medals if necessary.

He pointed out that, for most of the period covered by the allegations, the head of the IAAF’s Medical Commission was Arne Ljungqvist, the Swede considered a pioneer in anti-doping.

Approached subsequently, Diack poured scorn on any notion that the IAAF’s testing between 2001 and 2012 had not been done properly.

"We have nothing to hide," he said.

He insisted the latest episode did not cast a shadow over the 2015 World Athletics Championships, set to take place in Beijing later this month.



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