Patraeus resigns

CIA Director David Petraeus resigned as head of the leading U.S. spy agency on Friday, saying he had engaged in an extramarital affair and acknowledging he "showed extremely poor judgment."

In a letter to the CIA workforce, Petraeus, 60, said he met with President Barack Obama at the White House on Thursday and asked "to be allowed, for personal reasons, to resign from my position."

"After being married for 37 years, I showed extremely poor judgment by engaging in an extramarital affair," he wrote. "Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours."

Obama, who was re-elected to a second term on Tuesday, said in a statement he had accepted Petraeus' resignation, praising him for his work at the CIA and for leading U.S. troops in Iraq and Afghanistan.

Petraeus' revelation of the affair appeared to end the public career of a widely admired warrior-scholar who played a key role in the Iraq war, led the U.S. Central Command and commanded U.S. and NATO troops in Afghanistan.