WADA vice-president Linda Helleland has been left frustrated that the organisation could only give Russia a four-year ban from international sporting events.
"I'm not happy with the decision we made today. But this is as far as we could go," she is quoted as saying by AP.
"This is the biggest sports scandal the world has ever seen. I would expect now a full admission from the Russians and for them to apologize on all the pain all the athletes and sports fans have experienced."