The outgoing U.S. and NATO led International Security Assistance Force (ISAF) commander, Gen. David Petraeus second left, hands over the flag to US military commander James Mattis head of US Central Command during a changing of command ceremony in Kabul, Afghanistan on Monday, July 18, 2011. Gen. John Allen took over command of American and coalition forces in Afghanistan on Monday from Gen. David Petraeus, assuming responsibility as Afghanistan’s international allies draw up exit plans from the nearly 10-year conflict.(AP Photo/Musadeq Sadeq)

In this photo taken Feb 12, 2011 Ahmad Wali Karzai, left, half brother of Afghan President Hamid Karzai talks to an aid during an interview with the Associated Press at his house in Kandahar. An Afghan official says Afghan President Hamid Karzai’s half brother has been killed in southern Afghanistan. Zalmai Ayubi, the spokesman for Kandahar province, says that Ahmad Wali Karzai was shot dead on Tuesday July 12, 2011. Ahmad Wali Karzai, who was head of the Kandahar provincial council, had become a political liability for the Karzai government _ a symbol of cronyism and a lightning rod for criticism of all that is wrong with the Karzai administration. (AP Photo/Anja Niedringhaus)

Afghan National Army soldiers and US Army soldiers from the 1-320th Alpha Battery, 2nd Brigade of the 101st Airborne Division stand guard after an insurgent attack at COP Nolen, in the volatile Arghandab Valley, Kandahar, Afghanistan, Friday, July 23, 2010. (AP Photo/Rodrigo Abd)

(AP Photo/Ahmad Massoud)