Italian rider Ricardo Ricco' of the Saunier Duval-Scott team has tested positive for blood booster erythropoietin (EPO), the French national anti-doping agency (AFLD) confirmed on Thursday.

The 24-year-old Ricco' , winner of two mountain stages, provided a urine sample which contained the banned subtance CERA (Continuous Erythropietin Receptor Activator) after the fourth stage, a 29.5 km time-trial at Cholet. His Saunier-Duval team later confirmed they were withdrawing from the race. "We've decided to suspend all cycling activities until we find out what has happened," team director Matxin Fernandez said.

"Ricco' is not just any rider, he's a top rider. So for the sake of our team and the Tour de France we have made this decision. We can't act as though nothing has happened, we have to accept the reality." The Italian won stages six and nine and was in ninth position overall 2min 29sec behind Australian race leader Cadel Evans. His Spanish teammate Juan Jose Cobo was in eighth position. Veteran team member Leonardo Piepoli won Monday's tenth stage.

Ricco' was questioned by gendarmes before the start of Thursday's 12th stage between Lavelanet and Narbonne. He was then driven away by them in a Saunier Duval team car. Ricco was one of the riders particularly targeted by the AFLD during the race and had been tested at least four times, French sports daily L'Equipe reported earlier on their website. Ricco was one of the riders particularly targeted by the AFLD during the race and had been tested at least four times, including his victories on stages six and nine.

Like synthetic erythropoietin (rEPO), CERA was developed to as a treatment for the anemia that results from chronic kidney disease. Unlike single injections of rEPO, CERA interacts with erythropoietin receptors and has a longer-lasting effect.

The often brash and outspoken Ricco finished second in this year’s Giro d’Italia and has won stages six and nine at this year’s Tour de France. He finished Wednesday’s stage 2:29 behind Australian Cadel Evans in the overall standings, putting him in ninth place. All tests on the Tour are being carried out by AFLD because the race is being held under the auspices of the French federation. That decision came in the wake of an ongoing conflict between the International Cycling Union (UCI) and the company which runs the Tour, ASO (Amaury Sports Organisation). Ricco' thus becomes the third rider to fail a drugs test in this year's race after Spanish riders Moises Duenas of Barloworld and Manuel Beltran of Liquigas also tested positive for EPO.