The World Anti-Doping Agency has confirmed that a Russian cyber espionage group by the name of Tsar Team or Fancy Bears gained illegal access to WADA’s Anti-Doping Administration and Management System database via an International Olympic Committee-created account for the Rio Olympics. The group accessed athlete data, including confidential medical information related to the Games.

The hacking group, was also blamed by WADA on Tuesday for posting data about U.S. athletes Simone Biles, and Serena and Venus Williams. That information showed the three women had applied for, and received, therapeutic use exemptions for otherwise banned substances.

WADA announced on Thursday the data of other athletes, including similar information about the medication used by British cyclists Bradley Wiggins and Chris Froome, as being among 25 Olympic athletes who were targeted from the sports of boxing, cycling, rowing, shooting, swimming and tennis.

Citing law enforcement sources, WADA said the attacks “are originating out of Russia.” Russian officials dismissed the allegation.