Landis was the centre of attention at a hectic news conference

The American, 30, tested positive for unusual levels of testosterone after winning stage 17 of the race.

Speaking at a news conference in Madrid, Landis said the testosterone was "absolutely natural and produced by my own organism".

Landis, of the Phonak team, awaits the result of a B sample test this week.

News conference: Floyd Landis

He said he would request "within hours" that a second sample he gave be tested but did not know when the result of that would be known.

"I want it (the result) to be made public immediately, I see no reason why not," he said.

I'm proud that I won the Tour because I was the strongest guy there Floyd Landis

Landis said he has naturally high testosterone levels and will agree to undergo tests to prove his case.

"We will explain to the world why this is not a doping case but a natural occurrence," he said.

"I would like to (make it) absolutely clear that I'm not in any doping process. In this particular case, nobody can talk about doping."

He said: "I ask not to be judged and much less sentenced by anyone" and added his victory in the Tour was "the result of many years of training and complete devotion to the sport".

Landis produced one of the most memorable rides in Tour history when he stormed to victory in stage 17 by almost six minutes.

The win put him back into contention for the yellow jersey a day after his chances looked to have evaporated when he cracked on the final climb of stage 16.

Asked whether he thought the timing of his failed test was significant, Landis said: "I was tested six other times during the Tour.

"Where it came up, I don't know what relevance that has. I'm quite proud of that day. I was the strongest guy and I deserved to win the stage."

And Landis remained insistent he was the worthy champion in Paris last Sunday.