Doping files of some US Athletes including Serena Williams has been leaked, the World Anti-Doping Agency (Wada) says.
According to a BBC report, WADA condemned Russian Hackers for leaking the confidential medical files of US Olympic athletes.
Athletes affected include tennis players Venus and Serena Williams and teenage gymnast Simone Biles.
WADA said in a statement that the action was part of plot to undermine the global anti-doping system by the Russian group, “Fancy Bears” which claimed responsibility for hacking the database.
Russian government spokesman Dmitry Peskov said it was “out of the question” that the Kremlin or secret services were involved in the hacking, Russian news agencies reported.
The hackers accessed records detailing “Therapeutic Use Exemptions” (TUEs), which allow the use of banned substances due to athletes’ verified medical needs.
Recall that Russian athletes were banned from the Rio Olympics following the recommendation of WADA over an alleged state-backed doping programme.
The anti-doping agency however insist that the action of the Russian group had further compromised effort to re-establish trust in Russia,” Wada director-general Olivier Niggli said.
Mr Niggli said Wada was experiencing almost daily cyber attacks originating from Russia.
Simone Biles, who won four gold medals in Rio, had obtained the necessary permission to take prescription medicine on the Wada banned drugs list, USA Gymnastics said in a statement.
“By virtue of the TUE, Biles has not broken any drug-testing regulations, including at the Olympic Games in Rio,” it said.
“Simone and everyone at USA Gymnastics believe in the importance of a level playing field for all athletes.”
However, the hackers, Fancy Bears said TUEs amount to “licences for doping”.
But US Anti-Doping Agency chief Travis Tygart called the hack “cowardly and despicable”.
“In each of the situations, the athlete has done everything right in adhering to the global rules for obtaining permission to use a needed medication,” he said.
Fancy Bears has also promised to release confidential records from other national Olympic teams.