A former laboratory chief, Grigory Rodchenkov, has made extensive claims, including that urine samples were switched to ensure athletes tested clean.
The World Anti Doping Agency says it will consider re-testing if necessary.
A former laboratory chief, Grigory Rodchenkov, has made extensive claims, including that urine samples were switched to ensure athletes tested clean.
The World Anti Doping Agency says it will consider re-testing if necessary.