On Monday, Maria Sharapova, a five-time Grand Slam champion, said that earlier this year she had tested positive for meldonium, an anti-ischemic drug used in Eastern Europe and the former Soviet Union to treat heart conditions.
The incident comes following the World Anti-Doping Agency (WADA) November report, in which the agency accused Russia of numerous breaches of global anti-doping regulations and recommended the country be banned from international athletics competitions.
Earlier on Tuesday, Russian Sports Minister Vitaly Mutko stated that several Russian athletes may be banned from sport over the use of meldonium, while mass disqualifications are not expected.
WADA banned meldonium from use by athletes on January 1, 2016. The agency considers the drug to be a metabolic modulator that increases athletes' endurance and shortens post-exercise rehabilitation time, as well as enhancing central nervous system activation.