The Court of Arbitration for Sport on Thursday upheld the Rio Olympic ban levied on Russia’s track and field teams after multiple investigations uncovered a systemic, government-run doping operation that had been in place for years.

The sanction, handed down earlier this year by the International Association of Athletics Federations, could be extended to all of Russia’s athletic teams at this year’s Olympics, which begin Aug. 5. The International Olympic Committee said earlier this week that it would weigh its legal options over a full-scale Russian ban and would use Thursday’s CAS ruling as a guideline.

Russia’s Olympic Committee had appealed the IAAF ban to the CAS on behalf of 68 athletes who were not implicated in the doping scheme, but the court sided with world track and field’s governing body, a decision decried by the Kremlin.

“I certainly regret such a decision by the Court of Arbitration for Sport which refers to absolutely all of our athletes,” spokesman Dmitry Peskov said, per Reuters. “The principle of collective responsibility is hardly acceptable.”

On Monday, the World Anti-Doping Agency released the results of an investigation, confirming earlier media reports that uncovered a government-run doping operation in Russia that began after a poor showing at the 2010 Winter Olympics in Vancouver. In response, the IOC said it would consider banning Russia from the Rio Olympics entirely. That decision is expected by Sunday at the latest.

The CAS also ruled that some Russian athletes could compete in Rio under a neutral flag if they meet a certain number of criteria, such as being drug-tested outside the country.