Former CIA Director David Petraeus apologised for the extramarital affair that forced his November resignation and acknowledged the toll it took on his family, career and reputation.

His appearance at an event honouring University of Southern California veterans and Reserve Officers' Training Corps students on Tuesday was his first public speech since the storied Army general's career was cut short by the scandal.

Petraeus noted that "life doesn't stop with such a mistake. It can and must go on."

"I know that I can never fully assuage the pain that I inflicted on those closest to me and on a number of others," Petraeus said.

"I can, however, try to move forward in a manner that is consistent with the values to which I subscribed before slipping my moorings and, as best as possible, to make amends to those I have hurt and let down."

Petraeus received standing ovations before and after his speech, which mostly focused on the problems veterans face when returning from war.

Sex scandal

The sex scandal involving Petraeus and his biographer, Paula Broadwell, an Army reserve intelligence officer who is also married, provided fodder for comedians and triggered a media storm that followed his confession and resignation.

It was a stunning downfall for a revered military man who was seen as one of the top American leaders of his generation and was once considered a potential contender for the White House.

Petraeus was crediting with helping pull Iraq from the brink of all-out civil war as commander there and President Barack Obama turned to him to lead U.S. forces in Afghanistan before moving to him to the CIA in 2011.

Petraeus insisted on hanging up his military uniform before taking over the civilian spy agency.

Source: Agencies