Gen. David Petraeus will step down as the top US commander in Iraq on Sept. 16, handing the reins to Lt. Gen. Raymond Odierno, the No. 2 commander there until recently, Reuters reports. Petraeus, who led the troop surge that ushered in a major decline in Iraq violence, will become head of Central Command, which oversees a region from Kenya to Kazakhstan. (More David Petraeus stories.)