The International Olympic Committee on Tuesday banned Russia from competing in the 2018 Winter Olympics in Pyeongchang, South Korea.

Olympic leaders made their decision in response to an ongoing investigation that has found evidence of widespread doping among Russian athletes, coaches and officials. Authorities have also alleged that a Russian testing lab tampered with samples taken from its athletes during the 2014 Sochi Winter Games.

Russian athletes who can prove they have competed cleanly will be allowed to compete in Pyeongchang under a neutral flag, the IOC said.

The announcement followed a day of debate among the members of the IOC executive board, who are meeting in Lausanne, Switzerland, this week.

“The IOC took a strong and principled decision,” said U.S. Olympic Committee CEO Scott Blackmun. “There were no perfect options, but this decision will clearly make it less likely that this ever happens again. Now it is time to look ahead to Pyeongchang.”

Two years ago, the IOC took a different approach, asking the individual federations that govern each sport to decide on eligibility. As a result, only a portion of the Russian team was allowed to participate in the 2016 Summer Olympics in Rio de Janeiro.