A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)

“Free Syrian Army” fighters walk past children in the eastern al-Ghouta, near Damascus July 29, 2013. (Photo by Bassam Khabieh/Reuters)

Ahmed, the 7 year old son of a FSA fighter, stands in front of a barricade, were he assits his FSA comrades in the neighborhood of Salahadeen, one of Aleppo's front lines. Aleppo, Syria, on March 27, 2013. (Photo by Sebastiano Tomada/Sipa Press USA)

Young “Free Syrian Army” fighters pose for a picture on a couch in Old Aleppo, November 3, 2013. The Arabic words written on the wall read: “God, Syria, Free”. (Photo by Molhem Barakat/Reuters)

Issa, 10 years old, carries a mortar shell in a weapons factory of the Free Syrian Army in Aleppo, September 7, 2013. Issa works with his father in the factory for ten hours every day except on Fridays. (Photo by Hamid Khatib/Reuters)

“Free Syrian Army” fighters walk along a damaged street filled with debris in Deir al-Zor, eastern Syria December 5, 2013. (Photo by Khalil Ashawi/Reuters)

A Syrian rebel plays football in the Saif al-Dawlah neighborhood of Aleppo, Syria, Wednesday, January 2, 2013. (Photo by Andoni Lubacki/AP Photo)

A Syrian man carries donated food supplies from an aid distribution centre in Aleppo on September 13, 2012. (Photo by Marco Longari/AFP Photo)

“Free Syrian Army” fighters sit in a house on the outskirts of Aleppo, Syria, Tuesday, June 12, 2012. (Photo by AP Photo)

Classes coninue at the school in Adthar, a village under opposition control in Idlib province, Syria, on November 19, 2012. The school was closed for safety reasons, but has since been reopened. (Photo by Bradley Secker/Demotix)

A “Free Syrian Army” fighter combs his hair as he looks at a mirror in the old city of Aleppo November 20, 2013. (Photo by Molhem Barakat/Reuters)

A “Free Syrian Army” fighter stands with his weapon beside Al-Moalimeen tower on the Jobar neighbourhood frontline in Damascus November 30, 2013. (Photo by Rafat Beram/Reuters)

Women, who are part of “Sawt al-Haq” (Voice of Rights), stand with their weapons as they undergo military training in Aleppo February 17, 2013. (Photo by Muzaffar Salman/Reuters)

Children ride on a makeshift merry-go-round made from remnants of Russian bombs at a basement in the Duma neighbourhood in Damascus, on the second day of Eid al-Adha October 16, 2013. (Photo by Bassam Khabieh/Reuters)

A “Free Syrian Army” fighter pats a cat as he sits with a fellow fighter and an elderly woman in Deir al-Zor, eastern Syria December 4, 2013. (Photo by Khalil Ashawi/Reuters)

A “Free Syrian Army” fighter takes up position inside a room as he aims his weapon behind sandbags in the old city of Aleppo November 29, 2013. (Photo by Mahmoud Hebbo/Reuters)

A “Free Syrian Army” fighter mans an anti-aircraft weapon in the old city of Aleppo November 29, 2013. (Photo by Mahmoud Hebbo/Reuters)

In this Friday, September 27, 2013 photo, a displaced Syrian woman comforts her one-month old grandchild Fatima inside a stone house near Kafer Rouma, in ancient ruins used as temporary shelter by those families who have fled from the heavy fighting and shelling in the Idlib province countryside of Syria. (Photo by Narciso Contreras/AP Photo)

A “Free Syrian Army” fighter exercises as he is seen through a hole in a wall in the Seif El Dawla neighbourhood in Aleppo November 14, 2013. (Photo by Malek Al Shemali/Reuters)

“Free Syrian Army” fighters sit around a fire along a street in Deir al-Zor, eastern Syria December 6, 2013. (Photo by Khalil Ashawi/Reuters)

Fighters from the Tawhid Brigade, which operates under the “Free Syrian Army”, rest as a fellow fighter smokes a cigarette near the 80th Brigade base in Aleppo November 12, 2013. (Photo by Molhem Barakat/Reuters)

Residents run from a fire at a gasoline and oil shop in Aleppo's Bustan Al-Qasr neighbourhood October 20, 2013. Witnesses said the fire was caused by a bullet fired by a sniper loyal to Syrian President Bashar al-Assad at the Karaj al-Hajez crossing, a passageway separating Aleppo's Bustan al-Qasr, which is under the rebels' control and Al-Masharqa neighborhood, an area controlled by the regime. (Photo by Haleem Al-Halabi/Reuters)

A “Free Syrian Army” fighter (L) looks at his comrade as he gets shot by sniper fire during heavy fighting in the Ain Tarma neighbourhood of Damascus January 30, 2013. (Photo by Goran Tomasevic/Reuters)

Syrian rebels rest during clashes with Syrian troops in Aleppo, Syria, on November 15, 2012. (Photo by Khalil Hamra/AP Photo)

Syrian rebel fighter, who goes by the name Saqir Abu Zahid, 22, a former University student, poses for a picture after returning from fighting Syrian forces in Aleppo at a rebel headquarters in Marea on the outskirts of Aleppo city, Syria, Sunday, August 26, 2012. (Photo by Muhammed Muheisen/AP Photo)

A portrait of a “Free Syrian Army” rebel mounted of his steed in Al-Shatouria village near to the Turkish border in northwestern Syria, on March 16, 2012. (Photo by Giogos Moutafis/AFP Photo)

A boy drinks water from a burst water pipe in Aleppo's Karm al-Jabal district, June 2, 2013. (Photo by Muzaffar Salman/Reuters)

Syrian rebels attend a training session in Maaret Ikhwan, near Idlib, Syria, Monday, December 17, 2012. (Photo by Muhammed Muheisen/AP Photo)

A girl stands on debris next to a damaged building at a besieged area of Homs, August 2, 2012. (Photo by Yazen Homsy/Reuters)