International Cycling Union president Pat McQuaid said a second positive drug test by Floyd Landis 'would be regrettable for cycling.' ((Giuseppe Aresu/Associated Press))

The head of cycling's world governing body was talking tough Friday, a day after Tour de France winner Floyd Landis tested positive for elevated levels of testosterone.

Pat McQuaid, president of the International Cycling Union, promised to wage "a crusade against doping," but cautioned, "we have to wait for the B sample before we can start the sanctioning process."

McQuaid added a second positive test "would be regrettable for cycling," but would also prove measures taken by theunion and the sports world to fight against doping are working.

He declined comment on the plan to ensure a positive test doesn't occur in the future.

"Whatever decisions we have to take we will take to gain the upper ground against these guys," McQuaid said in a phone interview from Dublin, Ireland.

"There's no doubt, I'm very angered by [news of Landis's positive test]."

McQuaid added the backup sample would probably be tested in the next two weeks following a request by Landis's Switzerland-based Phonak team.

Suspension pending results

Phonak has suspended Landis pending the results and said it would fire him if they came back positive.

Even if his B sample turns out to be clean, Landis admitted during a teleconference Thursdaythat he wouldn't be able to escape the cloud of suspicion following him.

"Unfortunately, I don't think it's ever going to go away no matter what happens next," he said. "It appears as though this is a bigger story than winning the Tour, so that's going to be hard to go away."

In an interview with Sports Illustrated's website, Landis denied taking performance-enhancing drugs to win the Tour de France.

Landis,an American,told that elevated levels of testosterone are common among cyclists and that he is retaining the services of Spanish doctor Luis Hernandez to help prove his innocence.

Landis's positive test is the latest embarrassment for cycling's biggest race.

Remarkable comeback

The opening of the Tour was rocked by a doping scandal, with several of the sport's top riders barred from the race after being implicated in a major investigation in Spain.

The 2006 Tourwrapped up Sunday with Landis capturing the three-week cycling race after the final stage through central Paris and down the city's famed Champs Elysée.

In one of the greatest comebacks in the history of the Tour, Landis embarked on a 120-kilometre solo breakaway to win Stage 17 by a whopping six minutes. That remarkable effort pushed him up to third in the overall standings as he whittled second-place finisher Oscar Pereiro's lead to a mere 30 seconds.

Landis finished third in Stage 19, a 57-kilometre individual time trial, to leapfrog Pereiro and reclaim the yellow jersey as overall leader, setting the stage for Sunday's procession into Paris, where he was crowned champion, succeeding seven-time winner Lance Armstrong.

With files from the Associated Press