A man on a motorcycle rides past a mortar shell in the northern Syrian town of Kobani January 30, 2015. (Photo by Osman Orsal/Reuters)





Fighters from Suqour al-Sham Brigade, which is part of the Free Syrian Army, carry a wounded member of their brigade during what activists said were clashes with forces of Syria's President Bashar al-Assad, in the al-Arbaeen mountain area of western Idlib January 30, 2015. (Photo by Khalil Ashawi/Reuters)





Fighters from the Suqour al-Sham Brigade, which is part of the Free Syrian Army, take cover from snipers behind a tank during what activists said were clashes with forces of Syria's President Bashar al-Assad, in the al-Arbaeen mountain area of western Idlib January 30, 2015. (Photo by Khalil Ashawi/Reuters)





Kurdish refugees from the Syrian town of Kobani wait for food distributed during lunch time at a refugee camp in the border town of Suruc, Sanliurfa province January 31, 2015. (Photo by Umit Bektas/Reuters)





Residents look for belongings amid damage from what activists said were air strikes by forces of Syria's President Bashar al-Assad in Saida village, in Deraa province February 1, 2015. (Photo by Wsam Almokdad/Reuters)





Children play with toy weapons along a street in the al-Jazmati neighbourhood of Aleppo February 1, 2015. (Photo by Hosam Katan/Reuters)





Schoolchildren stand on debris and carry balloons as they are gathering to express solidarity ahead of the International Childhood Cancer Day in Karm al-Jabal neighbourhood of Aleppo February 4, 2015. (Photo by Hosam Katan/Reuters)





A rebel fighter takes position as he aims his weapon behind piled cement blocks at Sheikh Najjar frontline against forces loyal to Syria's President Bashar al-Assad in Aleppo February 4, 2015. (Photo by Hosam Katan/Reuters)





An injured girl is transported to a field hospital after what activists said were at least 20 air strikes by forces loyal to Syria's President Bashar al-Assad in the Douma neighbourhood of Damascus February 5, 2015. (Photo by Mohammed Badra/Reuters)





A rebel fighter from the Free Syrian Army's Al Rahman legion covers his ears during the launching of a mortar at the frontline against forces loyal to Syria's President Bashar al-Assad in the besieged town of Arbeen in the eastern Ghouta of Damascus February 19, 2015. (Photo by Yousef Homs/Reuters)





A rebel fighter of al-Jabha al-Shamiya (the Shamiya Front) fires his weapon at the frontline against Islamic State fighters on the outskirts of Mare town, north of Aleppo March 24, 2015. (Photo by Sultan Kitaz/Reuters)





Rebel fighters of al-Jabha al-Shamiya (the Shamiya Front) walk along orchards on their way back from the frontline against Islamic State fighters on the outskirts of Mare town, north of Aleppo March 24, 2015. (Photo by Sultan Kitaz/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement fire from a tank during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. An alliance of Syrian Islamist rebels including al Qaeda's official wing said they had launched an offensive on Tuesday to take the northwestern city of Idlib, which is close to the main strategic highway linking Damascus to Aleppo. (Photo by Khalil Ashawi/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement sit inside a BMP armoured vehicle during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement fire a heavy machine gun during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





An injured rebel fighter from the Ahrar al-Sham Islamic Movement lies on the ground during what the rebel fighters said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement help an injured fellow fighter during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement help an injured fellow fighter during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement prepare their ammunition during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





Rebel fighters from the Ahrar al-Sham Islamic Movement help an injured fellow fighter during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)





A boy stands near a Free Syrian Army tank in Aleppo's Karm al-Jabal district March 26, 2015. (Photo by Mahmoud Hebbo/Reuters)





Shamiyah Front fighters prepare locally made shells before firing them towards forces loyal to Syria's President Bashar Al-Assad in the old city of Aleppo April 10, 2015. (Photo by Abdalrhman Ismail/Reuters)





Rebel fighters fire a locally made weapon towards forces loyal to Syria's president Bashar Al-Assad in Aleppo April 11, 2015. (Photo by Rami Zayat/Reuters)





Rebel fighters pray in Jisr al-Shughour town after they took control of the area April 25, 2015. (Photo by Ammar Abdullah/Reuters)





Nusra Front fighters ride a military vehicle that they seized from forces loyal to Syria's president Bashar Al-Assad in Jisr al-Shughour town after rebels took control of the area April 25, 2015. (Photo by Ammar Abdullah/Reuters)





Residents flee Jisr al-Shughour town after rebels took control of the area April 25, 2015. (Photo by Ammar Abdullah/Reuters)





Residents flee Jisr al-Shughour town after rebels took control of the area April 25, 2015. (Photo by Ammar Abdullah/Reuters)





Residents stand upon the rubble of collapsed buildings after what activists said was shelling by forces loyal to Syria's President Bashar Al-Assad at Ain Tarma in eastern Ghouta, a suburb of Damascus, Syria April 26, 2015. (Photo by Amer Almohibany/Reuters)





A man carries a child who survived after he was pulled from under rubble following what activists said was shelling by forces loyal to Syria's President Bashar al-Assad at Ain Tarma in eastern Ghouta, a suburb of Damascus, Syria April 26, 2015. (Photo by Amer Almohibany/Reuters)





Residents walk upon the rubble of collapsed buildings after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad at Ain Tarma in eastern Ghouta, a suburb of Damascus, Syria April 26, 2015. (Photo by Amer Almohibany/Reuters)





Children walk amid the rubble of collapsed buildings after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad at Ain Tarma in eastern Ghouta, a suburb of Damascus, Syria April 26, 2015. (Photo by Amer Almohibany/Reuters)





Rebel fighters inspect a site damaged by what activists said was shelling by warplanes loyal to Syria's President Bashar al-Assad in Jisr al-Shughour town, after the rebels took control of the area, April 26, 2015. (Photo by Khalil Ashawi/Reuters)





Free Syrian Amy fighters run with their weapons fearing snipers loyal to Syria's president Bashar Al-Assad during clashes in Old Aleppo, April 26, 2015. (Photo by Abdalrhman Ismail/Reuters)





Free Syrian Army fighters carry their weapons during clashes with forces loyal to Syria's president Bashar Al-Assad in Old Aleppo, April 26, 2015. (Photo by Abdalrhman Ismail/Reuters)





Free Syrian Amy fighters stand with their weapons prior to clashes with forces loyal to Syria's president Bashar Al-Assad during clashes in Old Aleppo, April 26, 2015. (Photo by Abdalrhman Ismail/Reuters)





A damaged military truck that belonged to forces loyal to Syria's President Bashar al-Assad is seen in Qarmeed camp after Islamist rebel fighters took control of the area, April 26, 2015. (Photo by Abdalghne Karoof/Reuters)





Islamist rebel fighters stand on a tank that belonged to forces loyal to Syria's President Bashar al-Assad in Qarmeed camp after the rebels took control of the area, April 26, 2015. (Photo by Abdalghne Karoof/Reuters)





A rebel fighter rides a motorbike along a road in Qarmeed camp, as smoke rises in the background after Islamist rebel fighters took control of the area from forces of Syria's President Bashar al-Assad, April 27, 2015. (Photo by Abdalghne Karoof/Reuters)





A mother and her son mourn the loss of their relatives caused by what activists say was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad, in Aleppo's al-Fardous district April 29, 2015. (Photo by Mahmoud Hebbo/Reuters)





A father and his daughter mourn the loss of their relatives to what activists say was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad, in Aleppo's al-Fardous district April 29, 2015. (Photo by Hosam Katan/Reuters)





A man reacts at a site hit by what activists say was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad, in Aleppo's al-Fardous district April 29, 2015. (Photo by Hosam Katan/Reuters)





Rebel fighters of “Ahrar Jableh” brigade prepare to launch a mortar in the Jabal al-Akrad area in Syria's northwestern Latakia province April 28, 2015. (Photo by Khalil Ashawi/Reuters)





A man carries a child at a site hit by what activists say was a barrel bomb dropped by forces loyal to Syria's President Bashar al-Assad, in al-Kalaseh neighbourhood in Aleppo April 29, 2015. (Photo by Hosam Katan/Reuters)





A makeshift vase and telephone made from remnants of mortar shells are placed inside Abu Khaled's shop in the Douma neighborhood of Damascus April 28, 2015. Abu Khaled opened a shop for making “barley bread” using remnants of weapons including rockets, tank shells and other ordnance fired by forces loyal to Syria's President Bashar al-Assad. (Photo by Amer Almohibany/Reuters)





A Free Syrian Army fighter repairs a weapon at the Yarmouk Palestinian refugee camp April 29, 2015. (Photo by Ward Al-Keswani/Reuters)





Tajammu Al-Ezza brigade fighters fire an anti-aircraft weapon towards what activists said were helicopters loyal to Syria's president Bashar Al-Assad located in Hama countryside May 6, 2015. (Photo by Mohamad Bayoush/Reuters)





A Tajammu al-Ezza brigade fighter reacts as he fires a mortar shell towards forces loyal to Syria's president Bashar Al-Assad located on Al-Zlakiet checkpoint in Hama countryside May 6, 2015. (Photo by Mohamad Bayoush/Reuters)





Tajammu Al-Ezza brigade fighters prepare locally made shells before firing towards forces loyal to Syria's president Bashar Al-Assad located in Al-Lataminah village, Hama countryside May 6, 2015. (Photo by Mohamad Bayoush/Reuters)





Children play on the railway tracks at Tell i-Refat train station in the northern countryside of Aleppo May 6, 2015. The station that connects the district of Aleppo with Turkey is out of service since nearly three years due to the conflict in the country. (Photo by Hamid Khatib/Reuters)





Civilians react as they wear gas masks after what activists said was a chlorine gas attack on Kansafra village at Idlib countryside, Syria May 7, 2015. (Photo by Abed Kontar/Reuters)