"He accepted his wrongdoing and did not ask for a B sample," said Eric Boyer, manager of Moreni's Cofidis team.

Athletes who fail a doping test are entitled to ask for a follow-up "B'' sample test to confirm — and in rare cases refute — the results of the initial "A'' sample.

Police were seen leading Moreni away from the Cofidis team bus. It was unclear where they were taking him.

The French sports newspaper L'Equipe said on its Web site that Moreni tested positive for testosterone after stage 11 of the Tour last Thursday.

The test analysis for Moreni was conducted by the Chatenay-Malabry lab on the outskirts of Paris. Traces of testosterone were found in the urine sample, L'Equipe said. The test showed that the testosterone was administered and that the hormone was not naturally occurring.

A senior French doping official confirmed Wednesday that a Tour rider had tested positive for testosterone, although he did not know the identity of the rider. The official spoke on condition of anonymity because he was not authorized to discuss the case with reporters.

Moreni's positive test was the latest blow to a race already reeling from doping revelations. News of Moreni's test came a day after star rider Alexandre Vinokourov and his entire Astana team were sent home after he tested positive for a banned blood transfusion.

Moreni was in 54th place overall at the end of Wednesday's 16th stage, 1 hour, 56 minutes and 11 seconds behind overall leader Michael Rasmussen, who also won the stage.

The Danish cyclist crossed the finish line alone after the 135.8-mile ride from Orthez to Gourette-Col d'Aubisque, the toughest ride in the Pyrenees this year.

American Levi Leipheimer finished 26 seconds behind, and Discovery Channel teammate Alberto Contador of Spain was third, 35 seconds back. Both lost time against Rasmussen, who broke away from the three-man group in the last half-mile, finishing in 6 hours, 23 minutes, 21 seconds.

Rasmussen, who has faced doping suspicions this year, extended his lead to 3:10 against second-place Contador. He's 5:10 ahead of Cadel Evans of Australia. The three-week event ends in Paris on Sunday.

"I am one step closer," said Rasmussen, who won Stage 8 in Tignes.

And that's worrisome to some fans.

At the start Wednesday, fans booed Rasmussen, who is riding under a cloud of suspicion because he skipped doping tests before the three-week Tour began.

And dozens of riders staged a silent protest against the doping scandals in their sport _ delaying the start by 13 minutes.

Previously, Tour rider Patrick Sinkewitz had tested positive for elevated levels of testosterone. Sinkewitz has denied doping and asked for his B sample to be tested, with the results expected to be known by July 29.

Sinkewitz tested positive in training on June 8 _ a month before the Tour started _ but he competed in the race until he crashed into a spectator during the eighth stage on July 15.