Tour de France champion Floyd Landis tested positive for high levels of testosterone during the race, his Phonak team said Thursday on its Web site.

The statement came a day after the UCI, cycling's world governing body, said an unidentified rider had failed a drug test during the Tour.

And the statement came just four days after Landis stood on the victory podium on the Champs-Elysees, succeeding seven-time winner Lance Armstrong as an American winner in Paris.

Floyd Landis of the US checks the clock as he crosses the finish to place second of the 7th stage of the 93rd Tour de France cycling race, a 52-kilometer (32.3-mile) individual time trial between Saint-Gregoire and Rennes, western France, in this Saturday, July 8, 2006 file photo. Tour de France winner Landis failed to show up for a one day race in Denmark on Thursday July 27, 2006 a day after missing a scheduled event in the Netherlands. [AP]

The Swiss-based Phonak team said it was notified by the UCI on Wednesday that Landis' sample showed "an unusual level of testosterone/epitestosterone" when he was tested after stage 17 of the race last Thursday.

Landis made a remarkable comeback in that Alpine stage, racing far ahead of the field for a solo win that moved him from 11th to third in the overall standings. He regained the leader's yellow jersey two days later.

Landis rode the Tour with a degenerative hip condition that he has said will require surgery in the coming weeks or months.

Arlene Landis, his mother, said Thursday that she wouldn't blame her son if he was taking medication to treat the pain in his injured hip, but "if it's something worse than that, then he doesn't deserve to win."

"I didn't talk to him since that hit the fan, but I'm keeping things even keel until I know what the facts are," she said in a phone interview from her home in Farmersville, Pa. "I know that this is a temptation to every rider but I'm not going to jump to conclusions ... It disappoints me."

Phonak said Landis would ask for an analysis of his backup "B" sample "to prove either that this result is coming from a natural process or that this is resulting from a mistake."

"The team management and the rider were both totally surprised of this physiological result," the Phonak statement said.

Landis has been suspended by his team pending the results. If the second sample confirms the initial finding, he will be fired from the team, Phonak said.

Landis wrapped up his Tour de France win on Sunday, keeping the title in U.S. hands for the eighth straight year. Armstrong, long dogged by doping whispers and allegations, won the previous seven. Armstrong never has tested positive for drugs and vehemently has denied doping.

Speculation that Landis had tested positive spread earlier Thursday after he failed to show up for a one-day race in Denmark on Thursday. A day earlier, he missed a scheduled event in the Netherlands.

On the eve of the Tour's start, nine riders - including pre-race favorites Jan Ullrich and Ivan Basso - were ousted, implicated in a Spanish doping investigation.

The names of Ullrich and Basso turned up on a list of 56 cyclists who allegedly had contact with Spanish doctor Eufemiano Fuentes, who's at the center of the Spanish doping probe.