A member of the Afghan National Army searches a resident during a joint patrol with U.S. troops near Command Outpost AJK (short for Azim-Jan-Kariz, a nearby village) in Maiwand District, Kandahar Province, Afghanistan, February 1, 2013. REUTERS/Andrew Burton

An Afghan National Army (ANA) soldier keeps watch at a checkpoint on the outskirts of Jalalabad city June 12, 2014. REUTERS/Parwiz

An Afghan National Army (ANA) soldier is seen through damaged glass as he keeps watch at the Forward Base in Nari district near the army outpost in Kunar province, February 24, 2014. The Afghan Taliban killed 21 soldiers in the assault on Sunday in the remote mountainous region, the Afghan government said, and six soldiers were missing after the militants' most deadly assault on the security forces in months. The government sent reinforcements to the area where the pre-dawn attack took place, Afghan Defence Ministry spokesman Zahir Azimi said in a statement. REUTERS/Omar Sobhani

An Afghan National Army (ANA) soldier keeps watch at a checkpost in Logar province, Afghanistan February 16, 2016. NATO advisers want Afghan soldiers to spend less time manning checkpoints and more taking the fight to Taliban militants, a key tactical shift the coalition hopes will enable local forces to quell a rising insurgency. Picture taken February 16, 2016. REUTERS/Omar Sobhani TPX IMAGES OF THE DAY - RTX283UI

Afghan national army soldiers stand at their outpost at Shembawut village in Khowst province December 14, 2009. REUTERS/Zohra Bensemra

Afghan National Army members keep watch while Helmand Provincial Governor Gullab Mangal talks to Afghans on a street near Camp Hanson in Marjah district, Helmand province, April 3, 2010. REUTERS/Asmaa Waguih

An Afghan National Army (ANA) soldier looks out from the windshield of an armoured car at the Forward Base in Nari district, near their army outpost in Kunar province, February 24, 2014. The Afghan Taliban killed 21 soldiers in the assault on Sunday in the remote mountainous region, the Afghan government said, and six soldiers were missing after the militants' most deadly assault on the security forces in months. The government sent reinforcements to the area where the pre-dawn attack took place, Afghan Defence Ministry spokesman Zahir Azimi said in a statement. At bottom is a picture of Afghanistan’s President Hamid Karzai. REUTERS/Omar Sobhani

Afghan National Army (ANA) soldiers patrol around their base in Logar province, Afghanistan February 16, 2016. NATO advisers want Afghan soldiers to spend less time manning checkpoints and more taking the fight to Taliban militants, a key tactical shift the coalition hopes will enable local forces to quell a rising insurgency. Picture taken February 16, 2016. REUTERS/Omar Sobhani - RTX283UG

An Afghan National Army soldier keeps watch shortly before his patrol came under fire in the Taliban stronghold of Kolk in Zahri district, Kandahar province, southern Afghanistan, November 15, 2007. A joint Canadian-Afghan patrol came under fire on Thursday and the Canadian gunner of an armoured vehicle stationed nearby said he killed up to five attackers. No bodies were found when the patrol conducted a search 30 minutes after the clash. Insurgents usually remove the bodies of their dead from the battlefield. REUTERS/Finbarr O'Reilly

An Afghan National Army soldier carries his weapon after a battle with Taliban insurgents near Sangsar, Zhari district in southeastern Afghanistan, July 3, 2007. A suicide bomber dressed as a policeman killed five Afghan police and wounded 11 as he sat with them at a checkpoint in the southeastern town of Spin Boldak, a border police chief said. Picture taken July 3, 2007. REUTERS/ Finbarr O'Reilly

An Afghan Army soldier stands next to a fighting position at an observation post overlooking Combat Outpost Lowell in eastern Afghanistan January 9, 2009. REUTERS/Bob Strong

Afghan policemen stand guard at the site of a suicide bomb attack in an area near the Russian embassy in Kabul, Afghanistan January 20, 2016. REUTERS/Omar Sobhani - RTX238LJ

Afghan National Army (ANA) soldiers keep watch at a checkpoint in Logar province, Afghanistan February 16, 2016. NATO advisers want Afghan soldiers to spend less time manning checkpoints and more taking the fight to Taliban militants, a key tactical shift the coalition hopes will enable local forces to quell a rising insurgency. Picture taken February 16, 2016. REUTERS/Omar Sobhani - RTX283UL

An Afghan army soldier takes up position during a joint patrol with U.S. army soldiers from Delta Company, a part of Task Force 1-66, near the village of Mohammad D'Jakub, Arghandab River valley, Kandahar province, September 13, 2010. REUTERS/Oleg Popov Image used for illustrative purpose

An Afghan National Army (ANA) soldier takes a break after patrolling in Dand Ghori district of Baghlan province, Afghanistan March 15, 2016. REUTERS/Omar Sobhani - RTSAICK

Afghan National Army (ANA) soldiers arrive after a blast near the Pakistani consulate in Jalalabad, Afghanistan January 13, 2016. Afghan security forces exchanged fire with gunmen barricaded in a house near the Pakistan consulate in the eastern city of Jalalabad on Wednesday after a suicide bomber blew himself up, officials said. REUTERS/ Parwiz - RTX225M2

Afghan National Army (ANA) soldiers walk through a poppy field as they patrol in stronghold of Panjwaii in Kandahar province, southern Afghanistan, April 12, 2009. REUTERS/Stefano Rellandini

A member of the Afghan National Army provides security with a soldier from the U.S. Army's Bravo Company, 1st Battalion, 36th Infantry Regiment during a patrol near Command Outpost AJK (short for Azim-Jan-Kariz, a near-by village) in Maiwand District, Kandahar Province, Afghanistan, January 31, 2013. REUTERS/Andrew Burton

Afghan security forces take their positions at the hilltop of Dand Ghori district of Baghlan province, Afghanistan March 15, 2016. REUTERS/Omar Sobhani - RTSAIAW

An Afghan National Army (ANA) soldier keeps watch at the site of an attack by insurgents on a joint NATO-Afghan base in the Ghani Khel district of Nangarhar province January 4, 2014. REUTERS/Parwiz

A dust-covered Afghan National Army soldier with a flower tucked behind his ear rides on the back of a vehicle during a patrol near the Taliban stronghold of Panjwaii town, Kandahar province, southern Afghanistan, November 13, 2007. REUTERS/Finbarr O'Reilly

An Afghan army soldier rests during a joint foot patrol with U.S army soldiers from Task Force Denali Platoon 1-40 CAV between the villages of Melani and Molah-Chinah in Khowst province December 20, 2009. REUTERS/Zohra Bensemra

Afghan National Army soldier uses a basket as camouflage during an ambush in Zhari district of Kandahar province, southern Afghanistan, October 23, 2007. One Canadian soldier was lightly wounded and an Afghan National Army soldier was shot in the shoulder during heavy fighting on Tuesday in the volatile Mowz-e-Madad area of Kandahar province. REUTERS/Finbarr O'Reilly

An Afghan policeman keeps watch at a hilltop in Dand Ghori district of Baghlan province, Afghanistan March 15, 2016. REUTERS/Omar Sobhani - RTSAIBR

Afghan National Army (ANA) soldiers keep watch at a checkpost in Logar province, Afghanistan February 16, 2016. NATO advisers want Afghan soldiers to spend less time manning checkpoints and more taking the fight to Taliban militants, a key tactical shift the coalition hopes will enable local forces to quell a rising insurgency. Picture taken February 16, 2016. REUTERS/Omar Sobhani - RTX283UB

An Afghan National Army soldier sits beneath the national flag while waiting to go on patrol in the Taliban stronghold of Kolk in Zahri district, Kandahar province, southern Afghanistan, November 15, 2007. REUTERS/Finbarr O'Reilly