Floyd Landis, who on Sunday became the third U.S. cyclist to win the Tour de France after a seemingly spectacular mountain stage comeback, tested positive for a banned substance, his team announced today, throwing his history-making win into doubt.

The Swiss-based Phonak cycling team said Landis returned a positive test after Stage 17 last Thursday, one of the most remarkable rides in cycling history.

Phonak said Landis had been notified Wednesday by cycling's governing body, which goes by the acronym UCI, that the urine sample Landis provided after Stage 17 showed an "unusual level of testosterone/epitestosterone."

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

It also said Landis would ask for an analysis of the backup sample in a bid "to prove either that this result is coming from a natural process or that this is resulting from a mistake."

In the meantime, Phonak said, it had suspended Landis.

LaTimes