PYEONGCHANG, South Korea — Biathlon world champion Yekaterina Iourieva and two other Russians have been suspended for doping, officials said Friday on the eve of the world championships.

Follow-up tests confirmed positive results for Iourieva and teammates Albina Akhatova and Dmitri Yaroshenko, the International Biathlon Union said in Pyeongchang.

The federation provisionally suspended a number of athletes last week for testing positive for banned substances but did not identify the competitors.

The confirmation Friday comes as athletes prepare to compete in the first biathlon worlds to be held in Asia.

"We are facing systematic doping at the large scale in one of the strongest teams of the world," IBU President Anders Besseberg told reporters in the eastern resort town of Pyeongchang.

"Either we have been able to catch them all, or we have only seen the top of the ice mountain," he said. "There is no, absolutely no, excuse for what the three doped Russian athletes and the people behind them have done."

He did not disclose which banned substances were found in testing.

Iourieva leads the World Cup rankings with 567 points halfway through the season. She won gold in the women's 15-kilometer individual race at last year's worlds in Ostersund, Sweden — the same venue where the positive samples were collected at a World Cup competition in December 2008.

Since the initial test, Iourieva won the 7.5-kilometer sprint at Oberhof in January and the 12.5-kilometer mass start at Antholz-Anterselva.

Akhatova, a three-time world champion in mass start and relay, is sixth in the women's standings with 443 points.

Yaroshenko is 21st in the men's field with 203 points. He was on Russia's world champion relay team twice.

The three athletes will face an IBU disciplinary panel once the IBU receives full results from a testing laboratory in Lausanne, Switzerland.

They risk disqualifications and suspensions that could end their hopes of competing at the 2010 Winter Olympics in Vancouver.

The world championships kick off Saturday with the men's and women's sprint competitions.