London: The World Anti-Doping Agency (WADA) will immediately probe recent statements made by Russian ex-doping official Vitaly Stepanov on the abuse of performance enhancing drugs in Russian sports, its chief Craig Reedie has said.

Stepanov, a former employee of the Russian Anti-Doping Agency (RUSADA), stated in a 60-minute film aired by US TV channel CBS News last Sunday that at least four Russian gold medallists of the 2014 Winter Olympic Games were taking steroids, reports Tass.