PAU, France -- Overall leader Lance Armstrong and the rest of the top six riders in the Tour de France passed blood tests in their hotels Tuesday, the second rest day of the race, organizers said.

Armstrong, Germany's Jan Ullrich, Kazakhstan's Alexander Vinokourov, Spain's Haimar Zubeldia and Iban Mayo, and Italy's Ivan Basso were tested with their teammates.

The tests found that the cyclists' level of hematocrite -- red blood cells -- was below the 50 percent legal limit and they were all declared fit to continue the Tour.

During a 21-month investigation that was completed last year, French investigators found no proof that Armstrong's U.S. Postal Service team used banned substances during the 2000 Tour de France.

The investigation was launched after a French TV crew filmed U.S. Postal officials disposing of medical waste far from the team hotel during the 2000 Tour.

Armstrong, 30, has never failed a drug test and denies taking banned substances. He is trying to equal Miguel Indurain's record of five straight Tour victories.

Information from Reuters and The Associated Press was used in this report.