The World Anti-Doping Agency (Wada) is "disappointed" its recommendation to ban Russia from next month's Olympic Games in Rio has been rejected.Following the country's doping scandal, the International Olympic Committee has left it up to individual sports' federations to ban Russian competitors.
Wada "stands by" its recommendation last month of a full Russia team ban.
And Wada chief Olivier Niggli said the IOC's decision will "inevitably" mean "lesser protection for clean athletes".
Wada president Sir Craig Reedie said investigators had "exposed, beyond a reasonable doubt, a state-run doping program in Russia that seriously undermines the principles of clean sport embodied within the World Anti-Doping Code".
There was also concern expressed for Yuliya Stepanova, the Russian runner whose evidence helped expose her nation's doping scandal, but will now not be allowed to compete in Rio under a neutral flag.
"Wada has been very vocal in supporting Yuliya's desire to compete as an independent athlete," added Niggli.
"Ms Stepanova was instrumental in courageously exposing the single biggest doping scandal of all time. Wada is very concerned by the message that this sends whistleblowers for the future.
Russia decision 'a confusing mess'Olympic organisers have been accused of a lack of leadership and creating a "confusing mess" over the Russia decision.
The United States Anti-Doping Association (Usada) said the IOC had delivered a "significant blow to the rights of clean athletes".
"Many, including clean athletes and whistleblowers, have demonstrated courage and strength in confronting a culture of state-supported doping and corruption within Russia," said Usada chief Travis Tygart.
"Disappointingly, however, 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."he IOC also ruled that any Russian athlete who has served a doping ban will not be eligible for the Games.
That means it will not allow whistleblower Stepanova to compete as a neutral athlete in Rio.
Tygart added: "The decision to refuse her entry into the Games is incomprehensible and will undoubtedly deter whistleblowers in the future from coming forward."
Reaction to IOC Russia decisionRussian Sports Minister Vitaly Mutko: "We are very grateful to the International Olympic Committee for the fact that in choosing between collective responsibility and the rights of individual athletes, it took the decision that every athlete whose reputation today is untarnished, who is clean, without doping, has the right to compete in the Olympics."
UK Sports Minister Tracey Crouch: "While this is solely a decision for the International Olympic Committee, the scale of the evidence in the McLaren report arguably pointed to the need for stronger sanctions rather than leaving it to the international federations at this late stage."
British IOC member Adam Pengilly: "I believe that the Russian federation has mocked the Olympic movement and I worry about the future of clean sport, I worry about the future for clean athletes, the Olympic movement and the Olympic Games.
"Some have suggested the IOC has passed the buck and I'd have to agree. There's been an abdication of responsibility here."
World marathon record holder and four-time Olympian Paula Radcliffe: "While I applaud no athlete going to the Games who has previously served a doping suspension, this cannot fairly be only Russian athletes.
"A truly strong message for clean sport would have been to ban all those who have been caught cheating."
How the athletes see itSix-time Olympic track cycling champion Chris Hoy tweeted: "What sort of message does this send out? Surely IOC's job is to make crucial decisions rather than passing the buck."
Five-time Olympic distance runner Jo Pavey tweeted: "Such a disappointing decision by the IOC. Does not send out a strong message that doping will not be tolerated."
Double Olympic rowing gold medallist James Cracknell tweeted: "Bottled it - IOC passing the buck to individual federations (sports) on whether to allow Russian athletes to compete in Rio 2016. Bad day. Russian track & field appeal fails so their ban remains."
Olympic 400m bronze medallist Katharine Merry tweeted: "IOC are useless... like I said last week.. what EXACTLY would a country have to do to get a blanket ban? #cantshakemyheadhardenough."
Double Olympic gold medallist rower Andrew Hodge tweeted: "Decision based on promises from Russia, & leaving to the IFs is a poor move from a position on strength. Sad day."
American long-distance runner Kara Goucher tweeted: "So if you're Russian and served a drug ban you aren't allowed, but the US can send previously banned athletes. What?"