MOSCOW — Seven Russian women, many of them potential Olympic medalists, were banned for two years Monday by their country's federation for manipulating doping samples.

The international ruling body, however, disputes the timing of the suspensions that would allow the athletes to return to competition next year.

The International Association of Athletics Federations plans to challenge the decision at the Court of Arbitration for Sport in Lausanne, Switzerland.

The women had been provisionally suspended by track and field's governing body in July after a 1›-year investigation and missed the Beijing Games.

Among them are two-time world 1,500-meter champion Tatyana Tomashova and world indoor 1,500-meter champion Yelena Soboleva.

The others are distance runners Yuliya Fomenko and Svetlana Cherkasova, European discus champion Darya Pishchalnikova, former hammer world record-holder Gulfia Khanafeyeva and former world 5,000-meter champion Olga Yegorova.

The athletes faced out-of-competion drug tests in April-May 2007. The IAAF said the athletes had signed for urine samples that were not their own.

The Russian federation said Monday the start of the two-year bans will be backdated to the times of the tests. That means the athletes would be eligible to return next year, including for the world championships in Berlin.

Mikhail Butov, secretary general of the federation, said the decision was based on rules of the World Anti-Doping Agency.

"The IAAF was investigating the case for 16 months and neither we nor the athletes knew nothing all that time until the IAAF's decision to suspend them in July this year," he said. "The athletes missed the key start of the season and were stripped of all the results and prize money."

The IAAF, however, wants the bans to run from the time of the provisional suspension in late July 2008 to 2010.

"There is no way that we would accept any decision of the Russian federation to have 2-year bans starting from the time of the tests," an IAAF official told The Associated Press, speaking on condition of anonymity because the federation has not yet received the official documents from the Russians.

Suspicions about the Russians first surfaced in early 2007, when a string of exceptional results were matched by a long string of negative testing results. Experts started comparing their in-competition samples, which were clearly delivered by the athletes themselves, to those taken out of competition.