Alexandre Vinokourov - AP Photo/Alessandro Trovatii

PAU, France (Reuters):

Astana team leader Alexander Vinokourov failed a dope test after winning Saturday's Tour de France time trial, his team announced yesterday.

Vinokourov, who has won two stages in this year's race but was not in contention for the overall victory after finishing well behind the winner in Sunday's 14th stage, has left the Tour to go back to his Monaco residence.

Astana did not give any further details but a cycling source said the Kazakh had tested positive for blood doping.

"I cannot comment on thisuntil the result of the B sample's analysis," International Cycling Union (UCI) president Pat McQuaid told Reuters by telephone.

President of Tour organisers Amaury Sports Organisation Patrice Clerc and race director Christian Prudhomme were scheduled to hold a news conference.

British rider David Millar, who was holding a news conference in Pau when the news broke, said: "Jesus Christ, I'm speechless.

"It makes me sad. I have the impression the riders will never understand."

Millar served a two-year ban and was stripped of his gold medal from the 2003 World Championships after admitting taking the banned blood-booster EPO.

Vuelta champion Vinokourov was one of the pre-race favourites for this year's Tour but injured his knees in a crash during the first week of the race.

The 33-year-old then blew any hopes of victory when he finished almost half an hour down on stage winner Alberto Contador and overall leader Michael Rasmussen on Sunday.

Vinokourov, who won Monday's 15th stage, was 23rd in the overall standings, 28 minutes and 21 seconds behind yellow jersey holder Rasmussen of Denmark.