STRASBOURG, France (AP) -- A doping scandal knocked Tour de France favorites Jan Ullrich and Ivan Basso out of the race Friday and threw the world's most glamorous cycling event into chaos.

The decision to bar Ullrich, Basso and others implicated in a doping probe in Spain also sent a strong signal that cheating, or even suspicions of cheating, will not be tolerated.

Tour director Christian Prudhomme said organizers' determination to fight doping was "total."

"The enemy is not cycling, the enemy is doping," he said.

Riders being excluded will not be replaced, meaning a smaller field than the 189 racers originally expected.

It is the biggest doping crisis to the hit the sport since the Festina scandal in 1998 nearly derailed the Tour. The Festina team was ejected from the race after customs officers found a large stash of banned drugs in a team car.

Basso, winner of the Giro d'Italia, and Ullrich -- the 1997 Tour winner and a five-time runner-up -- were among more than 50 cyclists said to have been implicated in the probe that has rocked the sport for weeks.

Basso and Ullrich's teams said Friday that because their names had come up in the probe they were being withdrawn from the Tour, which begins Saturday. Ullrich's T-Mobile squad said it also suspended rider Oscar Sevilla and sporting director Rudi Pevenage because of their involvement.

Ullrich insisted he was innocent, and vowed to fight the allegations with help from his lawyer.

"The only thing I can say so far is that I'm shocked, that I still have nothing to do with this, that I'm a victim now and that I'm prepared (for the Tour) in this year like never before," Ullrich told reporters outside his hotel near Strasbourg, before leaving for home.

"This is the worst case of my career so far," he said. "I'll go on fighting at any rate. But at this moment, I'm desperate."

Basso was heading back to Italy, his team said.

The team of Spanish racer Francisco Mancebo, another top rider who finished fourth at the Tour last year, said it was withdrawing him.

A total of nine riders who signed up for the Tour were implicated in the Spanish probe, said cycling's governing body, the UCI. With the exception of Ullrich, Basso, Mancebo and Sevilla, the other riders were all with the Astana-Wurth team, whose former director was among those arrested in Spain.

The UCI identified the implicated Astana riders as Joseba Beloki of Spain, runner-up at the 2002 Tour and third in 2001 and 2000; Allan Davis from Australia; Alberto Contador and Isidro Nozal from Spain; and Sergio Paulinho from Portugal.

The team said it was trying to decide whether to withdraw them. Doing so would leave Astana with fewer than the minimum of six riders needed to start the Tour, which would force out the entire team -- including its pre-race favorite Alexandre Vinokourov from Kazakhstan.

At Astana, "it looks like a system of team doping," Prudhomme said.

Just a day earlier, the Court of Arbitration for Sport had ruled against Tour organizers' call for Astana to be barred from the race.

The Spanish scandal erupted in May when police there carried out arrests and raids, seizing drugs and frozen blood thought to have been readied for banned, performance-enhancing transfusions.

Since then, the names of riders said to have had contacts with Eufemiano Fuentes, a doctor among those arrested, have leaked in Spanish media.

Then, after more leaks on Thursday, Spanish authorities released details from the probe to Tour organizers and other cycling bodies, showing which riders were implicated in the investigation. It was on the basis of that official information that Tour teams decided to act.

The UCI noted that while the probe implicated the riders, it had not yet established that they had cheated. Nevertheless, Tour organizers pushed for their exclusion and teams agreed, in keeping with their ethical charter that allows riders to be barred from racing while they are under investigation for doping.

T-Mobile received information implicating Ullrich, Sevilla and Pevenage from Tour organizers, including documents from the Spanish government, team spokesman Luuc Eisenga said.

"The only thing I can tell you is that the information is clear enough and didn't leave any doubt," he said.

Another T-Mobile spokesman, Stefan Wagner, told Germany's n-tv television that the team was acting on information indicating "that there was contact between the two riders and Rudi Pevenage and the Spanish doctor ... who is at the center of this doping story."

Asked whether T-Mobile would consider cutting ties with Ullrich completely, he replied "certainly ... we are now demanding evidence of his innocence."

"If this evidence can be provided, then we have a completely new situation," he said. "If it cannot be provided, nothing will change about this situation."

German Interior Minister Wolfgang Schaeuble, who is responsible for sports, said: "This is a sad day."

"It can only strengthen us in pursuing the fight against doping with determination."

The extent of Basso's implication was not immediately clear. His team said that Basso insisted he was innocent. But it also said that the suspicion hanging over the Italian would have made his participation in the Tour difficult.

"It would be big chaos if those riders remain in the race," said the manager of Basso's team, Bjarne Riis. "We have to protect cycling."

Riis noted that Basso's contract forbids him from working with doctors from outside their CSC team.

"Ivan must prove with his lawyer that he is innocent," Riis said. "I believe in Ivan but I have been forced to take the necessary steps."