Lance Armstrong took another giant step toward a Tour de France victory today, and cycling's governing body said the only drug he has been taking is an authorized skin cream for saddle sores.

The 27-year-old Texan, making a startling comeback from testicular cancer, is just four days from what appears a probable triumph in cycling's showcase race.

But he has been dogged by suggestions in the French media that his success is linked to performance-enhancing drugs. He said today the strain of such accusations is affecting his outlook and his cycling.

"They want me to crack on the bike--and I'm not going to," he said after emerging from the last day of climbs in the Pyrenees mountains with a commanding lead of 6 minutes 15 seconds. "It's vulture journalism."

For two days, the French newspaper Le Monde reported traces of a corticosteroid were detected in his urine, and that of other riders as well.

Corticosteroids are anti-inflammatory and painkilling drugs that are not classified as steroids. They are banned unless prescribed by doctors for conditions such as asthma.

"I have been persecuted," Armstrong said. "It's bad for me, for cycling and for the Tour de France."