Five skiers representing Austria, Kazakhstan and Estonia have been arrested on Wednesday in anti-doping raids held at the Nordic Skiing World Championships in the Austrian resort of Seefeld.

The unexpected arrests were made in Austria and neighboring Germany as part of a combined raid aimed at targeting "a doping network operating worldwide."

READ MORE: Russian ski star gets yellow card for attack on opponent after crossing finish line (VIDEO)

Along with five skiers, four other people were also detained by police, whose names have not yet been revealed, according to Reuters.

Despite no official announcement, two out of the five top skiers arrested in Austria are allegedly Alexey Poltoranin from Kazakhstan and Estonia’s Andreas Veerpalu, the son of Estonian skiing legend and two-time Olympic champion Andrus Veerpalu.

The two skiers, who were set to compete in Wednesday’s 15km race, didn’t appear at the event due to unexpected police involvement.

Also on rt.com Austrian police question Russian biathlon team on suspicion of doping violations

One of the persons detained by the Austrian police is a doctor with reported links to doping in cycling.

“The Erfurt-based criminal group is strongly suspected of having been providing top athletes with banned substances for years to increase their performance in domestic and international competitions, thereby gaining illegal revenues,” Austrian police said in statement.

“The arrested athletes are two Austrian, one Kazakh and two Estonian top athletes. Among the detainees are also two police athletes from the national cross country team, who are currently undergoing basic police training.

READ MORE: ‘No evidence provided by Austria to show Russian biathletes guilty of doping’ – ambassador

At the same time, the 40-year-old sports physician Dr. med. Mark S. and another 40-year-old German accomplice arrested and nine house searches carried out. The investigations are still ongoing.”

Last year, Austrian police also carried out raids on the International Biathlon Union (IBU) headquarters in Salzburg and questioned Russian team members competing in Austria regarding suspected doping manipulations during the 2017 World Championships.

Taking banned performance-enhancing drugs is a serious crime in Austria, with athletes facing up to three years in prison if found guilty.