(CNN) The participation of 23 athletes in the Rio Olympics could be under threat, after doping samples gathered from London 2012 tested positive for banned substances.
A statement released by the International Olympic Committee (IOC) didn't reveal the athletes' names or nationalities, but said five sports and six countries were involved.
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Battling drug cheats
The World Anti-Doping Agency's (WADA) new report is the latest twist to hit the Russian doping scandal, building on Professor Richard Mclaren's initial findings, published in July, which concluded doping was widespread among Russian athletes.
More than 1,000 Russian athletes across 30 sports -- including football -- benefited from state-sponsored doping, according to the latest report.
The doping program, across summer, winter and Paralympic sports, was in operation from 2011 to 2015, said Mr McLaren, who presented his latest findings at a news conference in London Friday.
WADA's initial report on alleged widespread drug use in international athletics concluded that senior figures including IAAF president Sebastian Coe (pictured) "could not have been unaware of the extent of doping."
Former WADA president Dick Pound chaired a press conference held in Munich on January 14, 2016 to present the 89-page report. It said "corruption was embedded" and "cannot be blamed on a small number of miscreants" within the IAAF.
A report by the IAAF's ethics committee claims a powerful trio blackmailed Russian distance runner Lilya Shobukhova into paying them off to keep results of her positive drug tests secret.
Russia's former athletics president Valentin Balakhnichev, its ex-chief coach for long-distance athletes Alexei Melnikov and former IAAF consultant Papa Massata Diack have all been banned for life. The report said "far from supporting the anti-doping regime, they subverted it." The IAAF's former anti-doping director Gabriel Dollé has been given a five-year ban.
The report claims Balakhnichev, Melnikov and Papa Massata Diack "conspired together ... to conceal for more than three years anti-doping violations by an athlete at what appeared to be the highest pinnacle of her sport. All three compounded the vice of what they did by conspiring to extort what were in substance bribes from Shobukhova by acts of blackmail."
Pound produced an independent report in November 2015 which detailed systemic doping in Russia along with an establishment effort to cover it up. He recommended Russia be banned from athletic competition, which it duly was by the IAAF.
The findings uncovered a "deeply-rooted culture of cheating at all levels" within Russian athletics. Asked if it amounted to state-sponsored doping, Pound told reporters: "In the sense of consenting to it, there's no other conclusion."
The report suggested the London 2012 Olympics -- in which Russia won 24 gold medals and finished fourth -- was "in a sense, sabotaged by the admission of athletes who should have not been competing."
Pound's report detailed "corruption and bribery practices at the highest levels of international athletics," evidence of which has been given to international crime-fighting organization Interpol for further investigation.
Senegal's Lamine Diack, former president of the IAAF, is being investigated by French police over claims he accepted bribes to defer sanctions against drug cheats from Russia. French prosecutors claim he took "more than €1 million ($1M)" for his silence. Diack has yet to comment.
Coe, a former Olympic gold medalist, has come under fire for his praise for predecessor Diack, whom he called the sport's "spiritual leader" when he took over the role in August 2015. He told CNN he would "do anything to fix our sport."
The revelation comes just 10 days after 31 athletes from the 2008 Beijing Games also tested positive for banned substances.
"These reanalyses show, once again, our determination in the fight against doping," IOC President Thomas Bach said in a statement.
"We want to keep the dopers away from the Olympic Games in Rio de Janeiro. This is why we are acting swiftly now.
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"I have already appointed a disciplinary commission, which has the full power to take all the decisions on behalf of the IOC."
A total of 265 doping samples from London 2012 were retested, while one further sample from Beijing shows "abnormal parameters."
Friday's revelations -- "all based on intelligence-gathering that began in August 2015," the IOC said -- only serve to darken the cloud of controversy lingering over the Olympic movement.
Russia's track and field athletes are currently banned from international competition, a sanction which could prevent their participation in Rio 2016.
The Games begin on August 5.
"The reanalysis program is ongoing, with the possibility of more results in the coming weeks," the IOC statement continued.
"They are part of the IOC's efforts to protect the clean athletes by keeping dopers away from the Olympic Games Rio 2016 and protecting the integrity of the competition."
Further, the IOC says retesting of the 454 Beijing samples and 265 London samples was carried out using the very latest scientific analysis methods.
"The athletes, National Olympic Committees and International Federations concerned are already being informed, after which the proceedings against the athletes can begin," the IOC added.
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Rio Olympics: Torch arrives ahead of 2016 Games
Brazilian president Dilma Rousseff lit the Olympic torch in Brasilia Tuesday. The torch will pass through 329 cities on its way to Rio de Janeiro where the Games begin on August 5.
Brazilian sailor Felipe Rondina carried the Olympic flame on a speedboat at Lake Paranoa.
Canoeist Rubens Pompeu carried the Olympic flame on an outrigger canoe at Lake Paranoa. The torch will be carried in a relay by 12,000 people throughout its journey across the country.
The Olympic flame arrived on its own private flight form Switzerland. It was kept inside a gold lantern and transferred to Planalto presidential palace.
The Maracana stadium in Rio de Janeiro will host the opening ceremony of the Games which run from August 5-21.
"All athletes found to have infringed the anti-doping rules will be banned from competing at the Olympic Games Rio 2016."
The UK Anti-Doping (UKAD) said it welcomed the news from the IOC.
"Retrospective analysis allows us to pursue those who cheat clean athletes, long after the competition has ended," UKAD Director of Operations Pat Myhill said.
"It sends a clear message to those who dope -- if you chose to make that choice, and think that you've got away with it, think again. We can, and will, catch you."
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"Doping has a huge impact on the clean athletes - it takes away once in a lifetime opportunities," he added. "We can never replace those memories, but we can do our best to ensure that individuals who choose to steal those moments are caught and punished accordingly, and that clean athletes are rightly awarded the titles they train so hard to achieve."
Meanwhile, Kipchoge Keino, former Olympic athlete and President of National Olympic Committee of Kenya, said any athletes who were found to have used banned substances should be stripped of any medals they had won.
"I blame the people doing testing, those things should have been out earlier," he said. "Now when they are out at this moment, things should be discussed the medal should go.
"We don't want people who are cheating -- we need to get rid of those people."