The International Association of Athletics Federations, the governing body of track and field worldwide, said it was victim of a cyberattack on Monday, NBC News reported.
The infamous hacking group Fancy Bear was behind the attack, according to the IAAF. It said the group "compromised" athletes' applications that allows them to take otherwise banned substances for medicinal purposes.
While the group doesn't know if the files were extracted, the statement on their website noted the hackers' "strong indication of the attackers' interest and intent."
Fancy Bear was responsible for the hack that targeted the World Anti-Doping Agency last year, revealing information about U.S. Olympic athletes. Officials have previously linked Fancy Bear to GRU, the Russian military agency, but Russian officials deny the affiliation.