Russia has lost its appeal against the ban on its track and field athletes from competing in the Olympics in Rio de Janeiro.
The Court of Arbitration for Sport rejected on Thursday the appeal by 68 Russian track and field athletes seeking to overturn the ban imposed by the IAAF following allegations of state-sponsored doping and cover-ups.
The ruling could influence whether the entire Russian Olympic team is banned from the games.
Meanwhile, Russian Sports Minister Vitaly Mutko responded to the decision to ban Russian track and field athletes from competing in the Olympics in Rio de Janeiro on Thursday, saying it was "political."
Under Thursday's ruling in Lausanne, 68 Russian track and field athletes who were applying to compete in Rio will not be going to the Olympics.
Mutko told the Tass news agency that Russia will consider its further actions and lashed out at the verdict as unfair.
"In my view, it's a subjective decision, somewhat political and one with no legal basis," he was quoted as saying.
A spokesman for Russian President Vladimir Putin said Moscow regrets the court's decision.
Dmitry Peskov expressed regret over the ruling, adding that applying "collective responsibility (to all athletes) can hardly be acceptable."
A chronology of major events around revelations on systematic doping in Russian sport, and corruption affecting ruling athletics body IAAF.
December 3, 2014 - German broadcaster ARD alleges systematic doping, the cover-up of controls and corruption in Russian sport. It provides secret recordings and witness statements to back up the allegations.
December 4 - In response to the allegations, International Olympic Committee (IOC) president Thomas Bach promises a crackdown.
December 11 - Papa Massata Diack, son of then athletics governing body IAAF president Lamine Diack, leaves his marketing consultancy position with the IAAF and Valentin Balakhnichev resigns as IAAF treasurer.
December 12 - Gabriel Dolle resigns his position as director of the IAAF anti-doping unit.
December 16 - Former World Anti-Doping Agency (WADA) boss Dick Pound leads a three-person independent committee to investigate the allegations made of doping in elite Russian sport.
January 20, 2015 - The Russian Anti-Doping Agency (RUSADA) suspends five walkers, including three Olympic champions, for drug violations.
February 16 - Lamine Diack admits there is a "serious crisis" in relation to the allegations of doping in Russian sport.
February 17 - Balakhnichev resigns as head of the Russian Athletics Federation and is replaced by Vadim Zelichenok.
July 16 - Due to investigations into doping, the Russian federation withdraws the entire walking team from the August worlds in Beijing.
August 2 - ARD and the Sunday Times newspaper say they have a list of 12,000 blood values from 5,000 runners taken from 2001-2012 at Olympic Games and World Championships. It includes 800 athletes with values which indicate a suspicion of doping.
August 6 - A doping ban served by Liliya Shobukhova, a Russian winner of major global marathons, is extended by 14 months to March 2016. Shobukhova said in the ARD documentary she paid 450,000 euros (480,000 dollars) to cover up a positive test and compete at the London 2012 Olympics.
August 19 - Briton Sebastian Coe is elected new IAAF president.
November 4 - Lamine Diack is charged by French prosecutors and is accused of bribery and money laundering, along with his Papa Massata Diack, his lawyer Habib Cisse and Dolle.
November 6 - French prosecutor Eliane Houlette alleges Lamine Diack accepted more than 1 million euros (1.1 million dollars) during his time in office to cover up positive doping samples.
November 9 - The WADA independent committee publishes its report on doping in Russian elite sport. It recommends the IAAF should suspend Russia from competition, and that five athletes and five coaches be given lifetime doping bans.
November 10 - WADA suspend accreditation of Moscow doping laboratory, IOC provisionally suspend Diack as honorary member and call on IAAF and WADA "to consider all necessary action to be taken to protect the clean athletes and rebuild trust."
November 11 - Diack resigns as IOC honorary member and president of the International Athletics Foundation.
November 13 - The IAAF provisionally suspends the Russian federation in a move barring it from international track and field events. The suspension is for an indefinite period and could include next year's Olympics in Rio de Janeiro.
November 19 - The IAAF sets out five principals Russia must meet to be reinstated, with verification to be carried out by the IAAF.
November 26 - Russia accepts full suspension by IAAF and pledges to co-operate.
December 22 - Coe's office director, and former IAAF spokesman, Nick Davies steps down from his duties, pending the outcome of an ethics committee probe in connection with emails ahead of the 2013 worlds suggesting plans to delay Russian doping offenders.
January 7, 2016 - Papa Massata Diack is banned for life by the IAAF ethics commission over the Shobukhova allegations, along with Balakhnichev and Russian coach Alexei Menikov. Dolle is banned for five years.
January 14 - The WADA independent committee publishes the second part of its report. It says former IAAF president Diack "was responsible for organizing and enabling the conspiracy and corruption that took place." It said the IAAF council, which included now president Coe, could not have been unaware of the extent of doping in athletics, the level of nepotism in the IAAF and showed "an evident lack of political appetite ... to confront Russia."
March 7 - Russian tennis player Maria Sharapova says she failed a drug test at the Australian Open in January. The five-time Grand Slam winner tested positive for meldonium, a medication used to treat heart and circulatory conditions.
May 12 - The former head of the Moscow anti-doping lab, Gregori Rochenkov, tells the New York Times he was part of systematic manipulation of doping test results of Russian athletes at the Sochi 2014 Winter Olympics. He said 15 Russian medallists were doped.
May 28 - The Russian Olympic Committee says that eight of its athletes are among 23 who have tested positive in retests of 2012 Olympics. Russia said earlier that it also had 14 athletes from 31 caught in retests of 2008 samples.
June 15 - In another report, WADA says that 736 planned doping tests in Russia were thwarted through various means between February 19 and May 29. It said doping inspectors were obstructed, with reports of intimidation by agents from Russia's FSB security service, samples were tampered with and athletes attempted to cheat during tests.
June 17 - The IAAF says Russia's track and field team will be banned from taking part in the summer Olympic Games. However, athletes who can prove that they are clean can apply to compete in Rio de Janeiro as "neutral" competitors. Any individual athlete who has made an extraordinary contribution to the fight against doping in sport should also be able to apply for permission to compete.
June 21 - Russian officials say its clean athletes would appeal the IAAF ruling at the CAS if they can't compete at Rio Games. The IOC opens the door for some Russian athletes to compete at the Rio Games under the Russian flag - rather than a neutral flag - if they prove they were not doped.
July 11 - Sharapova's last chance of appearing at the Olympic Games ends when CAS says it would return a verdict on her appeal against a doping ban in September.
July 18 - WADA says state-controlled doping in Russia benefited athletes at summer and winter Olympics over at least a four-year period, and suggests that the IOC looks into a possible ban of all Russian athletes from the Rio Games.
July 20 - The IOC says it will reach a decision by July 26 on a ban of all Russian athletes.
July 21 - CAS dismisses the appeals of Russian track and field athletes and the nation's Olympic Committee against the IAAF ban, keeping them out of Rio Games.