CIA chief Petraeus in shock resignation over affair

'Other woman': Paula Broadwell, right, is married and has two children. Petraeus has been married to his wife Holly,left, for 37 years, they have two children

WASHINGTON, Nov 10 (AFP) - Washington was in shock Saturday after the sudden resignation of CIA chief and ex-US commander in Iraq and Afghanistan, David Petraeus, handing another major challenge to President Barack Obama just three days after his re-election.

Petraeus said he resigned over an extramarital affair, bringing an ignomious end to a highly praised military and government career. It also came shortly before the US spy chief had been due to testify in Congress on the agency's alleged failure to protect a US consulate in Libya from a deadly attack.

"After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair," the CIA director said in a message to staff, released to the media Friday.

Obama, in a written statement, acknowledged Petraeus's departure, praising his "intellectual rigor, dedication, and patriotism."But at the same time, he expressed confidence that the Central Intelligence Agency "will continue to thrive and carry out its essential

mis- sion" without the famed general.

The president, fresh off his electoral triumph, reportedly had no inkling that the CIA chief was about to resign until Thursday morning.

When he met with Petraeus later that day, Obama refused to accept the resignation straight away, saying he would think about it overnight, the New York Times said.

But in the end, Obama concluded he could not push Petraeus to stay on, according to the Times.

Michael Morell, Petraeus's deputy at the country's lead spy agency, will serve as acting director, but there were indications he might be only a temporary choice.

Speculation on a possible successor focused on John Brennan, the White House counter-terrorism adviser and CIA veteran who has played an instrumental role in Obama's drone war against AlQaeda militants.

Neither Petraeus nor the CIA explained exactly why he felt he had to step down over the affair, and whether his liaison presented a purely personal problem or raised security issues in his sensitive work as spy chief. FBI probe of biographer The affair came to light as the FBI was investigating whether a computer used by Petraeus had been compromised, the New York Times and other US media reported, citing government officials.

NBC News and other media reported the Federal Bureau of Investigation was investigating Paula Broadwell, co-author of a favorable biography of Petraeus, "All In: The Education of David Petraeus," for possible improper access to classified information.

Unnamed officials told the New York Times that Petraeus's lover was Broadwell, a former Army major who spent long periods interviewing Petraeus for her book. She offered no public comment on the revelations.

Experts noted that if Petraeus, a fourstar general who retired to take the CIA job, had committed adultery while still in the army, he could have been court-martialed.

The resignation comes amid criticism in some quarters of Petraeus over his response to the deadly attack in September on the US consulate in Benghazi, which killed the US ambassador to Libya and three other Americans.

After accepting the CIA chief's resignation, Obama hailed his "extraordinary service."

At the CIA, he had worked to shift the spy agency to a more "balanced" approach to intelligence gathering, after an intense focus on terror threats after the September 11, 2001 attacks, said Bruce Riedel, a former CIA officer and fellow at the Brookings Institution think tank.