The World Anti-Doping Agency (WADA) has expressed alarm over reports alleging that one-third of the medals awarded in top-level track-and-field endurance races over a 10-year period were won by athletes with suspicious blood tests.
Russian and Kenyan athletes featured prominently in the reports by the German broadcaster ARD and the British Sunday Times newspaper, who based the findings on 12,000 blood tests taken from 5,000 athletes competing in the Olympics and world championships from 2001 to 2012.
The reports found that 146 medals in endurance competitions were given to athletes who had registered suspicious blood values.
Fifty-five of the medals were gold, 80 were won by Russian athletes, and 18 by Kenyans.
None of the medals have been stripped, and the evidence is not proof of doping, according to the reports.
Nevertheless, WADA chief Craig Reedie said in a statement on August 2 that the cheating allegations will "shake the foundation of clean athletes worldwide."
The results were reportedly came from the database of the International Association of Athletics Federations and were leaked by a whistle-blower.