Petraeus oversaw a surge of tens of thousands of troops into Afghanistan in a last-ditch bid to reverse a nearly 10-year Taliban insurgency and although he has claimed some progress, violence remains at record highs.

He is leaving to head up the CIA, after a week in which Afghan President Hamid Karzai saw his younger brother and a key aide assassinated at their homes, and as NATO began transitioning areas of the country to Afghan control.