Paris  - Former Austrian cyclist Bernhard Kohl, in an interview with Tuesday's edition of French sports daily L'Equipe, gave details of his doping regime during the
2008 Tour de France and said that all top 10 riders could have failed doping tests there.

"I am convinced that the top 10 could have tested positive," Kohl said. "It is strange that only three (riders) were caught."

Kohl, Germany's Stefan Schumacher and Riccardo Ricci of Italy tested positive for the latest generation of the blood booster EPO, known as CERA, at post-race retests after a test method for the substance was developed.

"I did not cheat anyone in the peloton, that's for sure," he said.

Kohl said that "everyone in the cycling scene" was convinced that the latest EPO was undetectable.

Kohl originally finished third at the 2008 Tour behind Carlos Sastre of Spain and Australian Cadel Evans. He was also the king of the mountains at the race.

Kohl retired from cycling a few weeks ago after being banned over the positive test, and is now working together with anti-doping authorities.

The Austrian reiterated in the L'Equipe interview that he used illegal blood transfusions with the help of his manager three times during the Tour, but stopped taking other drugs like EPO, insulin and Human Growth Hormone before the Tour started.

Kohl also questioned the success of the biological passport made mandatory for riders by the ruling body UCI last year.

He said that no athlete has been caught for suspicious blood parameters and that the passport is in fact helpful for dopers because the parameters listed there served as a guideline for their doping practices.

The interview came one day ahead of an anti-doping conference in Paris. The 2009 Tour starts on July 4.(dpa)