Addressing a military audience in Los Angeles, the four-star general voiced regret for the "pain" caused by his relationship with his biographer Paula Broadwell, pledging to try to "make amends to those I have hurt and let down."

"I join you keenly aware that I am regarded in a different light now than I was a year ago," Petraeus told over 600 veterans and Reserve Officers' Training Corps students hosted by the University of Southern California (USC).