A spectator caused a horrific crash at the Tour of Italy on Thursday that left race leader Alberto Contador with a dislocated shoulder and another rider, Daniele Colli, with a broken arm, AFP reported.

WARNING: This post shows graphic images that some people may find disturbing.

As stage six of the race was nearing its climax with a sprint finish, Colli was racing up the side of the road when he struck a spectator's camera and telephoto lens before hitting the ground.

A moment later, race leader Contador went flying, too, along with several other riders, and ended up on the ground with a dislocated shoulder.

"The crash occurred in the final 300 meters as Daniele Colli hit the camera lens of a spectator leaning over the barrier and went down, bringing half the peloton down with him," the AP reported. "Colli was immediately taken to a hospital and his team confirmed he broke his arm."

Here's Colli, on the left, hitting the spectator's camera:



Here's another view:

Below is a video showing more of the crash and the aftermath.

WARNING: This video and an embedded tweet after it show graphic images that some people may find disturbing.

Colli later tweeted that he was doing OK, and he thanked all his well-wishers. He said it was unfortunate that he crashed because people were careless, adding that cyclists risk their lives every day and to please respect their work.

He also retweeted a photo of himself with his arm mangled and one with him giving the finger from his hospital bed:



As for Contador and his dislocated shoulder, he tweeted that he hopes to start Friday's stage seven.

Last Sunday, also in the Giro d'Italia, a spectator on a bike caused a big crash when he tried to ride along with the pros.

In the first few seconds of this video, you can see the guy riding right onto the racecourse:



The three-week Giro concludes on Sunday, May 30, in Milan. It is considered the most important stage race after the Tour de France.

The crash on Thursday overshadowed the impressive win by André Greipel:

The big question now is, will Contador actually start Friday's stage and be able to defend his lead?