The US Anti-Doping Agency (USADA) has given disgraced American cyclist Lance Armstrong two more weeks to co-operate fully in an investigation into cycling’s darkest episode in return for a possible reduction of his life ban.

Armstrong had initially been set a Feb. 6 deadline by USADA to answer questions under oath, but that was extended on Wednesday after the athlete’s attorney Timothy Herman said the timing for an interview could not be accommodated.

“We have been in communication with Mr Armstrong and his representatives and we understand that he does want to be part of the solution and assist in the effort to clean up the sport of cycling,” chief executive Travis Tygart said in a statement.

“We have agreed to his request for an additional two weeks to work on details to hopefully allow for this to happen.”

After years of denials, Armstrong admitted in an interview with Oprah Winfrey last month that he had cheated his way to a record seven Tour de France titles with systematic use of banned, performance-enhancing drugs.

Last year he was stripped of his titles after being labelled a “serial cheat” by the USADA.

Tygart then told the CBS “60 Minutes” programme on Jan. 27 that his agency had requested an interview with Armstrong while disputing the cyclist’s claims of a clean comeback in 2009.

“His blood tests in 2009, 2010 ... one to a million chance that it was due to something other than doping,” Tygart said.

In a letter to USADA on Jan. 25, Henman said his client was willing to co-operate with the agency but that pre-existing obligations made the Feb. 6 deadline impossible.