London Marathon chief executive Nick Bitel has said race organisers are "very concerned" by allegations in the Sunday Times that seven winners in a 12-year period recorded suspicious blood scores.
The newspaper has published fresh allegations following its analysis of drugs test data from 2001 to 2012.
It said the winners of 34 major marathons around the world - one in four - during the period should have faced censure or investigation because of their test results, with those athletes collecting more than £3million in prize money.
We believe there are people in our sport who are cheating and everyone has a part to play to protect those who are not.
We continue to be at the forefront of anti-doping measures for marathon runners as we are determined to make marathon running a safe haven from doping but we cannot do it all on our own and rely heavily on the IAAF.
We are therefore very concerned by the allegations made in the Sunday Times today and we will be discussing the implications of the allegations with the IAAF.
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The head of world athletics has said any suggestion his organisation had been negligent in drug testing was "laughable".
Lamine Diack, President of the International Association of Athletics Federation, told Reuters there was "no evidence" anything of the sort had taken place.
"There are allegations made. We want to look into them seriously because to say that in athletics between 2001 and 2012 we did not do a serious job with tests is laughable," he said.
The Sunday Times (£) reported obtaining secret data from the IAAF suggesting more than a third of medals had been won by athletes with "suspicious" blood test results.
Sports Minister Tracey Crouch said "everyone involved in sport must work together" following fresh claims of doping by Olympic athletes.
These are serious allegations and it is right they are being referred by the World Anti-Doping Agency (WADA) to its Independent Commission for investigation. I know UK Anti-Doping (UKAD), one of the best anti-doping agencies in the world, is also supporting this action, and has made it clear it will assist with WADA's enquiries.
UKAD has worked tirelessly to ensure athletes and sport are clean. But everyone involved in sport must work together to ensure we maintain the spirit of sport and prevent doping.
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Jessica Ennis-Hill has called on the IAAF and the World Anti-Doping Agency (Wada) to address the problem of doping after fresh claims of cheating.
"It is never good to hear of new possible doping offences in my sport, but if we are to stop a few athletes thinking cheating is acceptable, we have to explore all information that comes to light, however damaging it is for the sport as a whole", she said.
According to the Sunday Times (£), leaked data reveals that more than a third of medals - including 55 golds - have been won in endurance events at the Olympics and world championships by athletes who have recorded suspicious tests.
It is also alleged that a top UK athlete is among seven Britons with "suspicious" blood scores, while 10 medals were won at the London 2012 Olympics by athletes who have reportedly recorded dubious test results.
At least 800 athletes have recorded blood-test results described by an expert as "highly suggestive of doping or at the very least abnormal",the Sunday Times reports (£).
It follows what the newspaper says is the "biggest leak of blood-test data in sporting history"
The data, which belongs to the IAAF but was released by a whistleblower, also reportedly reveals:
- More than a third of Olympic and world championships medals - including 55 golds - have been won by athletes with suspicious doping test results.
- It is also alleged that a top UK athlete is among seven Britons with "suspicious" blood scores.
- Ten medals were won at the London 2012 Olympics by athletes who have reportedly recorded dubious test results.