METZ, France – A total of four riders quit the Tour de France Friday after suffering injury in the crash-marred sixth stage over 205 km from Epernay to Metz on Friday.

Dutchman Wouter Poels of Vacansoleil, one of several riders left sitting on the road in pain after a mass pile-up 26 km from the finish, has quit the race according to race officials.

American Tom Danielson, who had suffered a shoulder injury earlier this week, also pulled out after crashing at the same spot, where many of his Garmin teammates also came down.

Also caught in the crash were Italian Davide Vigano of Lampre and Spaniard Mikel Astarloza, who rides for Euskaltel. Both riders pulled out of the race.

It brings the number of retirements on the race to eight from the 198-strong peloton.

Dutchman Maarten Tjallingii (Rabobank), Jose Joaquin Rojas (Movistar) and Kanstantsin Sivtsov (Team Sky) had all quit prior to Friday's stage because of injuries suffered in crashes.

Germany Marcel Kittel of Argos-Shimano withdrew after 40km of racing Thursday having suffered from a stomach virus since Monday. – Sapa-AFP