AP: David Petraeus has resigned as director of the Central Intelligence Agency, the American spy agency, after admitting he had an extramarital affair.

According to his letter of resignation, Petraeus asked President Barack Obama on Thursday to allow him to resign, and on Friday the president accepted. Petraeus said in a statement that he had shown "extremely poor judgment" in having an affair.  

Image: David Petraeus |  Photograph: Jason Reed/Reuters