LOS ANGELES: David Petraeus apologised Tuesday night to an audience of veterans for the conduct that led to his resignation as head of the CIA following the disclosure of an extramarital affair.

Dressed in a civilian's dark suit and red tie, Petraeus gave his first public speech since his resignation in November, to a group of about 600 people, including many uniformed and decorated veterans at the University of Southern California's annual Reserve Officers' Training Corps dinner. The hero of the Iraq and Afghanistan wars has remained largely in seclusion since resigning. His lawyer, Robert B. Barnett, has said that Petraeus has spent much of that time with his family.

“Needless to say, I join you keenly aware that I am regarded in a different light now than I was a year ago,” Petraeus said.

“I am also keenly aware that the reason for my recent journey was my own doing. So please allow me to begin my remarks this evening by reiterating how deeply I regret and apologise for the circumstances that led to my resignation from the CIA and caused such pain for my family, friends and supporters.”

Petraeus received applause and a standing ovation before he began the evening's program by cutting a cake with a sword in military tradition, a task reserved for the highest ranking person in the room.

The retired four-star general's affair with his biographer, Paula Broadwell, was discovered during an FBI investigation into emails she sent to another woman she viewed as a rival for his attention.

“I know I can never fully assuage the pain that I inflicted on those closest to me and a number of others,” said Petraeus, in a somber tone to the audience that included his wife. He also mentioned their children.

At the time the affair was made public, Petraeus told his staff he was guilty of ‘extremely poor judgment.’

“Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours,” he said. On Tuesday night, Petraeus noted the challenges of transitioning from military life to civilian life, a path he is currently navigating.

“There's often a view that because an individual was a great soldier, he or she will naturally do well in the civilian world,” Petraeus said. “In reality, the transition from military service to civilian pursuits is often quite challenging.”

As the military leader credited with reshaping the US counterinsurgency strategy in both Iraq and Afghanistan, Petraeus had a friendly audience at the ROTC dinner. At least one expert in crisis communications said that if his apology comes across as heartfelt and sincere, the public will indeed be seeing much more of him.

“America is a very forgiving nation,” said Michael Levine who, among dozens of other celebrity clients, represented Michael Jackson during his first child molestation investigation.

“If he follows the path of humility, personal responsibility and contrition, I submit to you that he will be very successful in his ability to rehabilitate his image,” he said.

Another longtime crisis communications expert, Howard Bragman, said Petraeus has handled the situation perfectly so far and he expects he'll continue to do so. He noted that unlike former President Bill Clinton, former US Sen. John Edwards and other public figures caught in extramarital affairs, Petraeus didn't try to lie his way out of it, immediately took responsibility and moved on.

“I think the world is open to him now,” said Bragman, vice chairman of the image-building company Reputation.com. “I think he can do whatever he wants. Realistically, he can even run for public office, although I don't think he'd want to because he can make more money privately.”

Ahead of the speech, Petraeus drew lavish praise from USC's president, C. L. Max Nikias, who called him “arguably the most effective military commander since Gen. Dwight D. Eisenhower.”

“In our post 9/11 world, Gen. Petraeus' influence on our military is unmatched, and his contributions to the CIA are far-reaching.” Nikias said.

While at USC, Petraeus also planned to visit faculty and students at the Price School of Public Policy, which administers the ROTC program, and USC's School of Social Work, which trains social workers in how to best help veterans returning from war.

Petraeus was presented with a gift of silver cuff links by Nikias after his speech.