SAN JOSE, Calif. -- The confirmation that four U.S. track and field athletes tested positive for the newly discovered steroid THG means a review process will now begin, moving those athletes much closer to either being suspended or cleared of the drug charges.

A world track official said Wednesday that the backup B samples for all four athletes matched their positive A tests.

"We can now confirm all four are positive," Istvan Gyulai, general secretary of the International Association of Athletics Federations, told The Associated Press. Gyulai said he did not know the identity of the four athletes.

A source close to the investigation, speaking to the AP on condition of anonymity, has identified three of those athletes as 1,500-meter runner Regina Jacobs, shot putter Kevin Toth and hammer thrower John McEwen.

All four tested positive for THG at the U.S. championships at Stanford in June. Jacobs and Toth won national titles at that meet, and McEwen was a runner-up.

Now that the positive tests have been confirmed, the U.S. Anti-Doping Agency must appoint a panel that has about three weeks to recommend whether the case proceeds or is dismissed. If the case proceeds, the athletes can appeal. If ultimately found guilty, they face two-year bans.

An official announcement by the U.S. Olympic Committee of those cases proceeding would come about 30 days after the panel's recommendation.

British sprinter Dwain Chambers also tested positive on his A and B samples for THG, or tetrahydrogestrinone, in an out-of-competition test in August in Germany. Chambers, the European 100-meter champion, was suspended earlier this month by UK Athletics and his sanction was announced by the IAAF as soon as his B test concluded.

Gyulai called on U.S. officials to name the four athletes who have tested positive. U.S. officials have said such a move would violate privacy rules.

"This is the only country at the moment which doesn't give us the names right after the A (samples)," he said. "All the others provide the names. This little issue is still to be brought into line with IAAF regulations."

THG, a previously undetectable steroid, was unmasked last summer after an unidentified track coach gave a used syringe containing the substance to the USADA. The coach told USADA officials he got the substance from Victor Conte, founder of the Bay Area Laboratory Co-Operative that is now the target of a federal grand jury in San Francisco.

The IAAF has begun retesting 400 samples for THG from the world championships this August in France. Positive findings would result in retroactive disqualification, including stripping of medals and two-year bans.

The International Olympic Committee will decide by early next month whether to test urine samples from the 2002 Salt Lake City Olympics for THG.

IOC medical director Patrick Schamasch said Wednesday the organization still was considering legal and scientific issues before making a decision at the Dec. 4-5 meeting of its executive board in Lausanne, Switzerland.

Dr. Don Catlin, whose UCLA anti-doping laboratory handled drug testing at the 2002 Games and later unmasked THG, said last month that 200 to 300 samples from the Salt Lake City Olympics are stored at his lab.

The NFL, Major League Baseball and other pro leagues have said they will start testing for THG. The NCAA, which performs drug tests on 10,500 student athletes annually, also said it will begin to test for THG -- but will not conduct retroactive tests for the new steroid.