In his first Congressional appearance since resigning as the director of the CIA, retired Army Gen. David Petraeus apologized for sharing classified intel with his mistress and biographer Paula Broadwell.

“Four years ago, I made a serious mistake – one that brought discredit on me and pain to those closest to me,” Petraeus said. “It was a violation of the trust placed in me and a breach of the values to which I had been committed throughout my life.”

“There is nothing I can do to undo what I did. I can only say again how sorry I am to those I let down and then strive to go forward with a greater sense of humility and purpose, and with gratitude to those who stood with me during a very difficult chapter in my life.”

When it was discovered that Petraeus had shared unauthorized details with Broadwell, he was fined $100,000 and sentenced to two years probation.

In the same speech, Petraeus advised Congress and the Pentagon on how to deal with the situation in Syria, which he called a “geopolitical Chernobyl.”

“The central problem in Syria is that Sunni Arabs will not be willing partners against the Islamic State unless we commit to protect them and the broader Syrian population against all enemies, not just ISIS,” Petraeus said. “That means protecting them from the unrestricted warfare being waged against them by Bashar Assad, especially by his air force and its use of barrel bombs.”