U.S. Army Spc. Robert Zarlenga, a paratrooper with the 82nd Airborne Division’s 1st Brigade Combat Team, fires his M4 carbine at insurgent forces June 15, 2012, near Joint Security Station Hasan, southern Ghazni Province, Afghanistan. (U.S. Army photo by Sgt. Michael J. MacLeod, Task Force 1/82 PAO)

Spc. Shane Marks, 1st Battalion, 17th Infantry Regiment, 2nd Infantry Division, provides security in an overwatch position during Operation Southern Strike II in Afghanistan, June 6, 2012. (U.S. Army photo by Sgt. Brendan Mackie)

Spc. Shane Marks, 1st Battalion, 17th Infantry Regiment, 2nd Infantry Division, provides security in an overwatch position during Operation Southern Strike II in Afghanistan, June 6, 2012. (U.S. Army photo by Sgt. Brendan Mackie)

Soldiers from Alpha Battery of the 2nd Platoon, 2-77 Field Artillery fire a 155mm Howitzer towards insurgent positions at FOB Joyce in Afghanistan’s Kunar Province June 25, 2012. (REUTERS/Lucas Jackson)

US Army soldiers from Chosen Company fire mortar rounds at a Taliban firing position in Afghanistan’s eastern Paktia province. Photo By Sebastiano Tomada Piccolomini. (June 25, 2012)

A US Marine from Kilo Company of the 3rd Battalion 8th Marines Regiment patrols in Garmser, Helmand Province on June 24, 2012. The 130,000 NATO troops are due to leave Afghanistan by the end of 2014 and there are fears that their exit will lead to a reduction in rights and freedoms in the war-torn country. (AFP PHOTO / ADEK BERRY)

US Marine from Kilo Company of the 3rd Battalion 8th Marines Regiment patrols in Garmser, Helmand Province on June 24, 2012. The 130,000 NATO troops are due to leave Afghanistan by the end of 2014 and there are fears that their exit will lead to a reduction in rights and freedoms in the war-torn country. (AFP PHOTO / ADEK BERRY)