At least 99 athletes, including Olympic medalists and world champions, have tested positive in 2016 for meldonium, the performance-enhancing drug that tennis world No 7 Maria Sharapova admitted to using, according to the World Anti-Doping Agency. An official told The New York Times that the athletes include Semion Elistratov, a Russian Olympic gold medalist in short-track speedskating; Pavel Kulizhnikov, a Russian world champion speedskater; Davit Modzmanashvili, a Georgian Olympic silver medalist in wrestling; and Abeba Aregawi, a Swedish world champion runner.

Meldonium was placed on WADA's banned list this year after being monitored by the agency for 12 months, said the report. “The reason for it being on the list is it’s being used and has been used to enhance people’s performance,” said a spokesman for the agency, who added that players were given "ample warning". During her announcement on Monday, Sharapova had said that she was not aware meldonium was a banned substance, but accepted full responsibility for the failed test.

The 28-year-old will be provisionally suspended by the International Tennis Federation on Saturday and is awaiting a tribunal date. She could face a ban from competition for up to four years. Soon after her announcement, sportswear major Nike suspended its relationship with Sharapova. Swiss watch manufacturer Tag Heuer and luxury carmaker Porsche also terminated their contracts. However, sports equipment company Head, which has had an exclusive racket deal with Sharapova since 2011, declared its full support for her on Thursday.