The newspaper said the American's 'A' sample tested in a Paris laboratory showed traces of the blood-boosting substance. The 'B' sample was sent to another lab in Lausanne.

If the 'B' sample confirms the results of the tests in Paris, 27-year-old Young could face a lifetime ban and may also be stripped of his world title.

The tests were performed during the International Association of Athletics Federations (IAAF) Paris meeting at the Stade de France on July 23, where Young came sixth. The IAAF could not be reached for comment on Sunday morning.

Young, who failed to qualify for the Athens Olympics, had already tested positive for the banned anabolic steroid nandrolone in 1999.

However, he was cleared by the American governing body USA Track & Field (USATF) and competed at the Olympics in Sydney where he won a gold medal as a member of the 4x400 metres relay team that included five-times Olympic champion Michael Johnson.

The IAAF annulled the U.S. result last month but the International Olympic Committee (IOC) said on Saturday it was still waiting for that decision to be "final and enforceable" before deciding on a redistribution of the medals.

Young's compatriot Kelli White was stripped of her 100 and 200 metres world championship gold medals and suspended for two years after she confessed to having used EPO.