Alexander Vinokourov and his Astana team became the latest high-profile casualties in the war against doping on Tuesday, with cycling descending into chaos once again.

The Kazakh rider tested positive for blood-doping on the Tour de France [Images] after smashing his rivals in Saturday's time trial even though he had crashed heavily in the fifth stage to Autun.

Vinokourov, cheered by thousands of fans on his way to a second stage victory on Monday, was sacked by Astana, who pulled out of the race. The team's hotel in Pau was then raided by the gendarmerie.

"The doping test carried on Alexander Vinokourov after last Saturday's time trial in Albi has returned positive," the Swiss team backed by Kazakh companies said in a statement.

"There is the presence of a double population of haematids (blood corpuscles), which implies there has been a blood transfusion with homological (the same type of) blood."

"Tour organisers have asked Astana Cycling Team to leave the race, which has been accepted spontaneously."

The Vuelta champion has asked for his B sample to be analysed and has left Pau for his Monaco home.

BLOOD ANOMALIES

"We now have to wait for the B sample analysis results," Astana manager Marc Biver said. "It will be analysed before the end of the week.

"Vino denies any blood manipulation. He says after his crash on July 12, there may be blood anomalies.

"Leaving the Tour is a shock for the team. It's catastrophic. Everybody is shocked," he added."

International Cycling Union (UCI) president Pat McQuaid told Reuters he could not comment until after the B sample results were known.

Vinokourov's positive test is the latest in a series of doping scandals in the sport over recent years but Tour de France director Christian Prudhomme said the cheats would be chased down.

"I told the riders before the start that this was a fantastic opportunity for renewal," he said at a news conference.

"That has failed. But the cheats must understand that they are playing Russian roulette. We are utterly determined."

Pre-race favourite Vinokourov was 23rd in the overall standings, 28 minutes and 21 seconds behind yellow jersey holder Michael Rasmussen, who has been courting controversy himself.

The 33-year-old Dane, has received two warnings from the International Cycling Union (UCI) for failing to provide his whereabouts while training.

KLOEDEN FIFTH

Andreas Kloeden was Astana's best placed rider in the standings. The German, second in 2004 and third last year, was fifth overall, 5:34 down on Rasmussen.

Astana sacked Matthias Kessler earlier this month after the German rider tested positive for the elevated levels of testosterone.

Eddy Mazzoleni, who finished third in this year's Giro d'Italia, left the team in July because of involvement in a long-running Italian doping probe.

Mazzoleni, along with Giro champion Danilo Di Luca were asked to appear before Italian anti-doping authorities to explain their links to a doctor alleged to have supplied prohibited substances to athletes. The pair, who deny any wrongdoing, are waiting to hear whether they will be punished.

Astana withdrew on the eve of the 2006 race after five of Vinokourov's team mates were implicated in a blood-doping scandal, known as Operation Puerto, in Spain.

The investigation also left that Tour without 1997 winner Jan Ullrich, now retired, and 2006 Giro champion Ivan Basso, who has since been banned for two years after admitting attempting to dope.

Last year's Tour de France winner Floyd Landis is still awaiting a ruling from a United States arbitration panel after testing positive for testosterone during the 2006 race.

The American has protested his innocence but if the decision goes against him, he could become the first Tour champion to be stripped of his title.

(Additional reporting by Gilles Le Roc'h)