Speed skater Viktor Ahn, a six-time Olympic gold medalist, is among several top Russian athletes barred from the upcoming Pyeongchang Games amid the country's ongoing doping scandal, the Russian Olympic Committee said Tuesday.

The ROC says Ahn, as well as cross-country skier Sergei Ustyugov and biathlete Anton Shipulin — both reigning world champions — have been left out of an International Olympic Committee pool of eligible athletes.

ROC senior vice president Stanislav Pozdnyakov said in a statement that he discovered the absences during negotiations with IOC officials on Monday and has asked the IOC to explain why they were not included.

Pozdnyakov said the three athletes "have never been involved in any doping cases and all of the many samples they have given during their careers testify that they are clean athletes. Regardless, their names are currently missing from the list of potential participants in the Games."

Ahn, a short-track speed skater, won three gold medals for South Korea at the 2006 Olympics as Ahn Hyun-soo before switching allegiances to Russia in the run-up to the 2014 Winter Olympics in Sochi, where he won three more.

As punishment for what it termed a sophisticated Russian doping program at the 2014 Olympics, the International Olympic Committee has forced all Russians competing in Pyeongchang to do so as "Olympic Athletes from Russia" under the Olympic flag, rather than as an official Russian team.

Russian athletes must be vetted by an IOC commission, which will examine their history of drug testing and links to past doping, before they are invited to the Games.

On Friday, the IOC said it had cut an initial list of 500 Russian athletes down to a pool of 389, but didn't give any names. Russian officials have expressed hope they could field a team of 200 athletes. That's below the number that competed for Russia in 2014, but above its total from the 2010 Olympics in Vancouver.