IOC President Thomas Bach has urged authorities investigating an international doping ring to ensure the athletes and support staff involved are met with swift and tough sanctions ©IOC

International Olympic Committee (IOC) President Thomas Bach has urged authorities investigating a major doping ring to ensure the athletes and support staff involved are met with swift and tough sanctions.

Bach claimed those implicated should be given "hard" punishments to act as a deterrent following coordinated raids carried out at the Nordic Ski World Championships in Seefeld in Austria and in the German city of Erfurt last month.

At least 21 athletes from eight countries and five sports - three winter and two summer - are suspected of blood doping after police in Germany and Austria launched a targeted operation against what it believes is a worldwide drugs network.

Five athletes were arrested in Seefeld, while German team doctor Mark Schmidt - thought to be the mastermind of the operation - was detained in Erfurt.

The probe has since widened, with two cyclists, Stefan Denifl and Georg Preidler, admitting to their involvement.

Austrian skier Johannes Dürr, whose revelations about blood doping in a recent ARD documentary sparked the raids, was also arrested as part of the investigation.

The IOC had not publicly commented on the scandal, which prosecutors have warned could include other athletes and sports, until today, despite some of those involved admitting to blood doping at last year's Winter Olympics in Pyeongchang.

None of those involved were caught at the Games or at other major international events.

Raids were carried out last month at the Nordic World Ski Championships in Seefeld and in German city Erfurt ©Getty Images
Raids were carried out last month at the Nordic World Ski Championships in Seefeld and in German city Erfurt ©Getty Images

"We hope that all this will be clarified and everything will come on the table and there those responsible and the entourage of these athletes, the doctors and the personnel, that they will be punished soon and hard," Bach said following the IOC Executive Board meeting here.

"I hope that this does not drag on but their justice will really set an example and that there will be hard sanctions so that they can have a deterrent effect on everybody."

Max Hauke, an Austrian skier seemingly caught in the middle of a blood transfusion in Seefeld, four-time Kazakh Olympian Alexei Poltoranin and two Estonians, Karel Tammjarv and Andreas Veerpalu, were all arrested at the Championships before later being released.

According to German newspaper Frankfurter Allgemeine Zeitung, as many as 40 blood bags and other items associated with doping were seized during the raids in Germany, where two of Schmidt's associates were also detained.

German prosecutors allege the scheme had been in operation since 2011 until the arrests in Seefeld.

Blood was reportedly taken around the world to Germany, Austria, Italy, Sweden, Finland, Estonia, Croatia, Slovenia and the American state of Hawaii.