The World Anti-Doping Agency (WADA) has revealed that it was the victim of a cyberattack, which it has attributed to the Russian cyberespionage group, Tsar Team (APT28).

According to the agency, the group, which also goes by the moniker Fancy Bear, was able to gain access to its Anti-Doping Administration and Management System (ADAMS) database.

The group was able to locate confidential documents relating to several athletes, including the gymnast Simone Biles, and the tennis players Venus and Serena Williams. This information has subsequently been leaked.

Although this has not been officially confirmed by WADA, the agency did admit some sensitive data had been released “into the public domain”.

It added that the group behind the WADA cyberattack has warned that this is just the start – more confidential documents will reportedly be leaked.

“WADA deeply regrets this situation and is very conscious of the threat that it represents to athletes whose confidential information has been divulged through this criminal act,” commented Olivier Niggli, director general of the agency.

“WADA condemns these ongoing cyberattacks that are being carried out in an attempt to undermine WADA and the global anti-doping system.”

News of this comes on the back of WADA and the Court of Arbitration for Sport revealing last month that they had been targeted by cybercriminals.

Speaking to the Associated Press, Maggie Durand, communications coordinator at WADA, said at the time that phishing emails had been sent to numerous users of its database.

The cybercriminals had tried to pass off the emails as official communications, in which they requested login details to be shared.