IAAF president Lord Sebastian Coe has admitted that athletics faces a "long road to redemption" following fresh allegations of bribery to cover up past doping violations.
London 2012 medal winners are reportedly included on a list of eight athletes suspected of escaping bans for failed drugs tests.
According to The Sunday Times, the heads of world athletics were paid huge sums of money by those at risk of facing a ban so that they could compete at the Olympic Games.
The allegations, which are being investigated by French prosecutors, suggest that as much as €1.2m (£857,000) exchanged hands between the former president of the International Association of Athletics Federations and certain athletes.
"These are dark days for our sport," he told BBC Sport. "But I'm more determined than ever to rebuild the trust in our sport. However, this is a long road to redemption."
The ex-president of the IAAF, Lamine Diack, is under investigation on suspicion of corruption and money laundering.