"We know the tests are positive; we don't know the athletes involved," said international track federation (IAAF) spokesman Nick Davies. "There are no surprises (among B samples)."

Three of the four U.S. athletes are known: middle-distance runner Regina Jacobs, shot putter Kevin Toth and hammer thrower John McEwen. All were positive after their urine samples from June's U.S. track and field championships at Stanford were retested.

Each is entitled to a hearing overseen by the U.S. Anti-Doping Agency before a potential two-year ban. Howard Jacobs, who represents Toth and McEwen, estimates hearings won't be held until January.

Soccer

- MANCHESTER UNITED TO TOUR U.S. AGAIN: Manchester United is coming back to the United States for another preseason tour next summer. Coach Alex Ferguson announced Tuesday that the English Premier League champion will play three games in the United States. Two of the games will be at Giants Stadium and Chicago's Soldier Field. The site of the third game has not been finalized, but Foxboro, Mass.; Philadelphia; and Washington are the top contenders. Manchester United played four games on this year's tour, including one in Seattle.

-- The Associated Press