Armstrong blasts doping investigation

LOS ANGELES, June 23 (UPI) -- Cyclist Lance Armstrong fired back at U.S. doping officials, alleging shaky evidence and witnesses who were improperly pressured.

Armstrong's attorney Friday filed a response to the allegations leveled by the U.S. Anti-Doping Agency that portrayed the case as "long on stale accusations" with little hard evidence to back them up.

Attorney Robert Luskin said in his written response the case was "offensive to any notions of due process and fair play."

The USADA has recommended Armstrong be stripped of his seven Tour de France championships on the grounds of long-running use of performance-enhancing drugs. An agency official told the Los Angeles Times it could file formal charges against Armstrong as early as next week.