Two Russian wrestlers are the latest sportsmen to test positive for meldonium, the country's federation chief said Tuesday, as a scandal over the banned substance claimed more scalps.

Russian wrestling federation chief Mikhail Mamiashvili said that two of the country's wrestlers, 2014 world championship silver medallist Evgeny Saleyev and Sergei Semenov, the 2015 World Cup silver medal winner, have tested positive for the drug. The announcement came a day after Moscow announced four doping failures for meldonium in athletics, the first known cases of the banned drug in Russian athletics in a potential blow to efforts to be reinstated in time for the Rio de Janeiro Olympics.

The athletics federation did not name the four athletes who tested positive. It was unclear whether sprinter Nadezhda Kotlyarova, who admitted to taking the banned drug on Sunday, was among them. A number of high-profile Russian athletes, including tennis star Maria Sharapova, short-track speed skater Semyon Yelistratov and swimmer Yulia Yefimova, have tested positive for meldonium after it was added to the World Anti-Doping Agency's banned list on January 1.

Russia was suspended by the IAAF for other doping failures said to be "state sponsored". The IAAF will only decide in May whether Russian authorities have made enough effort to return to international competition. A taskforce from the IAAF that is meant to verify if Russia is now complying with anti-doping rules was in Moscow for the latest of its visits on Tuesday, meeting with the country's sporting officials. The IAAF is expected to issue a decision in May based on its taskforce reports whether Russian authorities have made enough efforts to return to international competition.