Danish cyclist Michael Rasmussen has admitted that he took performance-enhancing drugs between 1998 and 2010.

Rasmussen has already served a two-year suspension for evading doping controls during the 2007 Tour de France.

The 38-year-old was sacked by his Rabobank team and withdrawn from that year's Tour de France after lying about his whereabouts.

Rasmussen says he took testosterone and growth hormones and underwent blood transfusions in an effort to boost his performance.

Rasmussen says he intends to leave the sport with immediate effect and will co-operate with anti-doping agencies.

Rasmussen's revelations follow Lance Armstrong's admission that he took performance-enhancing drugs during his seven Tour de France wins.