Athletics world body, the IAAF, has banned long jumper Darya Klishina, Russia's only athlete allowed to take part in the Rio Olympics, the Court of Arbitration has confirmed.
Klishina made an immediate appeal to the court against the order, the tribunal said.
The International Association of Athletics Federations banned Russia because of an investigation which said there had been "state-sponsored" doping in Russia.
Klishina was originally allowed to compete in Rio because she was based in the United States and had regular testing outside Russia.
Meanwhile, Bulgarian runner Silvia Danekova branded the World Anti-Doping Agency (WADA) a "mafia in white aprons" who she is unable to fight to clear her name after failing a drugs test soon after arriving in Brazil.