The U.S. Anti-Doping Agency says the 37-year-old Klier - who now works for American team Garmin-Sharp as a sporting director - told the agency he used EPO, human growth hormone, cortisone and blood transfusions from 1999-2006.

Klier forfeits all results obtained from July 2005, including a stage win at the 2007 Vuelta a Espana.

USADA chief executive Travis Tygart says in a statement that the agency appreciates Klier's "willingness to provide full and truthful testimony about the culture of drug use in cycling."

Klier, who retired from riding in April, released the following statement:

"I have been involved in professional cycling for 17 years, and for those 17 years cycling has been my life. Some of my best memories and moments happened on my bike, and some of my worst too. Along the road to the top of the sport, many years ago, I chose the wrong path, and I have been very sorry for it ever since.  To everyone both in and out of cycling including my family, the fans, the sponsors, the sport I love, my peers, – especially those who made the right choices - I am deeply sorry."

"I stopped what I was doing and started competing clean well before I ever joined Slipstream, but I am proud today to be a part of an organization that makes racing clean its only priority. In my heart and my mind I know that telling the truth about my past to the proper authorities is the right thing to do to continue to help the sport I love move forward. I accept responsibility for the mistakes I made in my past and the punishment that comes along with them."

"I have seen both worlds of the sport and I believe that today it is in the best place its ever been. The young riders racing now have never faced the same choices I did, and I will do everything I can for the rest of my life to help continue to help build the sport that I love."

Team Garmin-Sharp, which owns Slipstream Sports, provided the following statement to the press:
 
"Slipstream Sports was created because we wanted to build a team where cyclists could compete 100% clean. We understood cycling’s history and we wanted to create a different environment for riders where they did not have to make the difficult choices of the past.  We support Andreas for telling the truth about his past, a past that pre-dates Slipstream Sports by years, and accepting the consequences that come along with it."

"Nothing can erase what happened in cycling’s history, but we can learn from it. We can look at the crop of young athletes coming up not just on our team but on other teams and have confidence that the future of the sport is here.  Cycling has never been cleaner and we will work, every day, to help it continue to progress."