The International Olympic Committee (IOC) failed to demonstrate “decisive leadership” when it declined to ban all Russian athletes from the Rio Olympics, the chief executive of the U.S. Anti-Doping Agency (USADA) said on Sunday.

The IOC resisted calls for a blanket ban on Russians competing in next month's Games due to the country's doping record, leaving decisions on individual athletes' participation with their sports federations.

“Disappointingly, in response to the most important moment for clean athletes and the integrity of the Olympic Games, the IOC has refused to take decisive leadership,” Travis Tygart said in a statement.

“The conflict of interest is glaring,” added Tygart, who had been outspoken in calling for a complete ban.

Tygart also had strong words for the IOC's failure to allow Russian whistleblower Yulia Stepanova to compete in Rio.

“The decision to refuse her entry in to the Games is incomprehensible and will undoubtedly deter whistleblowers in the future from coming forward,” the American said.

Revelations by the former drugs cheat and her husband helped expose the massive doping problem in her country. They are currently in hiding in the United States.

Tygart said many athletes and whistleblowers had the courage to confront the culture of state-supported doping in Russia.

“The decision regarding Russian participation and the confusing mess left in its wake is a significant blow to the rights of clean athletes,” Tygart added.

“It is so frustrating that in this incredibly important moment, they would pass the baton to sports federations who may lack the adequate expertise or collective will to appropriately address the situation within the short window prior to the Games. The conflict of interest is glaring.”