Five times Tour de France winner Lance Armstrong was involved in a massive crash after 13 kms in the 196-km sixth stage between Bonneval and Angers.

The American, who is trying for an unprecedented sixth Tour victory, was one of 30 riders involved in the pile-up which took place at the front of the bunch on Friday. He was not injured.

"It's nothing serious. He actually fell on the tarmac. There is not much you can do when a crash takes place just in front of you," said his U.S. Postal team chief Johan Bruyneel.

"In the first week of the Tour, riders are very nervous and you must be especially careful."

Armstrong is currently lying in sixth place overall, nine minutes and 35 seconds behind Frenchman Thomas Voeckler.