VAREZZE, Italy <197> Giro d'Italia leader Stefano Garzelli has failed a dope test, his Mapei team said on Saturday.

Team officials told a news conference the Italian rider, who won the Giro in 2000, had tested positive for probenecid, a diuretic and masking agent.

Garzelli, who strengthened his grip on the race by winning Friday's fifth stage, was being allowed to continue in the Giro pending the outcome of a second analysis of his sample on Tuesday, though the

"Garzelli shouldn't have started," International Cycling Union (UCI) press officer Enrico Carpani told Reuters. "It's a question of principle.

"There's an agreement between the teams, the organizers of the major tours and the UCI that a rider positive at a first test doesn't continue in the race. It doesn't matter if he is leading the race o

Carpani said the governing body would make a formal statement later on Saturday.

Mapei Manager Aldo Sassi said there were particular circumstances surrounding Garzelli's case.

"There is a general agreement but this is a particular situation," he told Reuters. "When we know the results of further tests we'll review our position." Race Director Carmine Castellano refused to c

The Mapei team said earlier they were surprised by the results of the test on Garzelli, which was carried out after Monday's stage to Liege, in Belgium.

"It's crazy that he would take something like this because it's certain to show up in a drugs test," said team press officer Alessandro Tegner.

Sassi added: "We don't want to say there's been a plot against us. We are just reporting the facts that we know. We've asked the UCI to test all our riders to see if they're positive for the same prod

"My conscience is clear," he said. "I have been preparing for the Giro since last year. I would be an idiot to ruin the race, my career and my life for something like this." Garzelli said he had heard

"I thought about stopping but the team convinced me to carry on," he said.