Syrians walk amid debris and destroyed buildings following a reported government airstrike on the rebel-held town of Douma, on the eastern outskirts of the capital Damascus, on late November 17, 2016. Douma, the largest town in the Eastern Ghouta area with more than 100,000 residents, is surrounded and regularly shelled by regime forces. (Photo by Sameer Al-Doumy/AFP Photo)





A Syrian boy practices basic arithmetic operations with a teacher during class in a barn that has been converted into a makeshift school to teach internally displaced children from areas under government control, in a rebel-held area of Daraa, in southern Syria on November 10, 2016. Rebels hold most of Daraa province, but the regional capital is largely controlled by the government. (Photo by Mohamad Abazeed/AFP Photo)





A woman sits facing two covered bodies at a make-shift morgue following government shelling on the rebel-held town of Douma, on the eastern outskirts of Damascus, on November 10, 2016. At least 11 people including four children were killed in air strikes on rebel-held areas near the Syrian capital, the Syrian Observatory for Human Rights said. (Photo by Abd Doumany/AFP Photo)





Shirin (L) and Kazîwar (R), members of the Kurdish female Women's Protection Units (YPJ) engage in conversation next to Kalashnikov assault rifles on a house rooftop in the Syrian village of Mazraat Khaled, some 40 kms away from the Islamic State group's (IS) de-facto capital of Raqa on November 9, 2016. (Photo by Delil Souleiman/AFP Photo)





Syrian women walk during a sandstorm near at a temporary refugee camp in the village of Ain Issa, housing people who fled Islamic State group's Syrian stronghold Raqa, some 50 kilometres (30 miles) north of the group's de facto capital on November 10, 2016. The US-backed Syrian Democratic Forces (SDF) said their advance on Raqa was being held back by a sandstorm that had hit the desert province. Speaking in Ain Issa, the main staging point for the operation some 50 kilometres (30 miles) north of Raqa, the commander said the sandstorm was also impeding visibility for coalition warplanes. (Photo by Delil Souleiman/AFP Photo)





A fully- veiled woman walks past unexploded mortar shells in the rebel- held town of Douma on the eastern outskirts of the capital Damascus on November 13, 2016 Douma, the largest town in the Eastern Ghouta area with more than 100,000 residents, is surrounded and regularly shelled by regime forces. (Photo by Abd Doumany/AFP Photo)





A wounded toddler waits to receive medical treatment after he hospitalized following an air-strike over the civilian populated residential areas in Douma district of Damascus on November 10, 2016. (Photo by Hamza Adnan/Anadolu Agency/Getty Images)





Blood stains the damaged ground after a strike on the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 8, 2016. (Photo by Bassam Khabieh/Reuters)





Civil Defence members run amidst debris after a strike on the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 8, 2016. (Photo by Bassam Khabieh/Reuters)





A man walks in a damaged site after a strike on the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria, November 8, 2016. (Photo by Bassam Khabieh/Reuters)





A blood stain is pictured near a hat on the ground after a strike on the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria, November 8, 2016. (Photo by Bassam Khabieh/Reuters)





An injured boy lies in a field hospital after a strike on the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria, November 8, 2016. (Photo by Bassam Khabieh/Reuters)





A family's fridge is pictured in the rebel-held besieged area of Aleppo, Syria November 12, 2016. (Photo by Abdalrhman Ismail/Reuters)





A girl uses her mobile phone inside a grocery shop with low supplies in the rebel-held besieged area of Aleppo, Syria November 12, 2016. (Photo by Abdalrhman Ismail/Reuters)





Children play in the rebel-held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 13, 2016. (Photo by Bassam Khabieh/Reuters)





A boy plays near the rubble of damaged buildings in the rebel-held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 13, 2016. (Photo by Bassam Khabieh/Reuters)





Children play near a damaged building in the rebel-held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 13, 2016. (Photo by Bassam Khabieh/Reuters)





A boy plays near the rubble of damaged buildings in the rebel-held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 13, 2016. (Photo by Bassam Khabieh/Reuters)





A boy stands near a disabled man in the rebel-held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 13, 2016. (Photo by Bassam Khabieh/Reuters)





A child plays with a balloon in the rebel-held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria November 13, 2016. (Photo by Bassam Khabieh/Reuters)





A man demonstrates how to use a homemade alcohol burner inside a workshop in the rebel-held besieged area of Aleppo, due to lack of cooking gas, Syria November 14, 2016. (Photo by Abdalrhman Ismail/Reuters)





A Free Syrian army fighter sits on a pick-up truck mounted with a weapon, as the supermoon partly covered by clouds is seen in the background, in the west of the rebel-held town of Dael, in Deraa Governorate, Syria November 14, 2016. (Photo by Alaa Al-Faqir/Reuters)





Residents of Hisha return to their town, after the Syrian Democratic Forces (SDF) took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





A woman carries a child as they return with others to the town of Hisha, after the Syrian Democratic Forces (SDF) took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





A Syrian Democratic Forces (SDF) fighter uses a mobile as he stands with his fellow fighters in the town of Hisha after they took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





Residents of Hisha return to their town as smoke rises in the background, after the Syrian Democratic Forces (SDF) took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





A boy walks his cows as he returns with others to their town of Hisha, after the Syrian Democratic Forces (SDF) took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





Residents of Hisha return to their town, after the Syrian Democratic Forces (SDF) took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





Residents of Hisha return to their town, after the Syrian Democratic Forces (SDF) took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





A Kurdish fighter from the People's Protection Units (YPG), operating alongside with the Syrian Democratic Forces (SDF), sits inside a vehicle as she works on a laptop in the town of Hisha after the SDF took control of the area from Islamic State militants, in the northern Raqqa countryside, Syria November 14, 2016. (Photo by Rodi Said/Reuters)





A man walks past the damage at a site hit yesterday by airstrikes in the rebel held besieged Douma neighbourhood of Damascus, Syria November 14, 2016. (Photo by Bassam Khabieh/Reuters)





Men dig a grave for 15-year-old Ziad Rihani, who was killed during shelling, ahead of his burial in a graveyard in the rebel held besieged Douma neighbourhood of Damascus, Syria November 14, 2016. (Photo by Bassam Khabieh/Reuters)





Men carry the body of 15-year-old Ziad Rihani, who was killed from shelling, prior to burial in a graveyard in the rebel held besieged Douma neighbourhood of Damascus, Syria November 14, 2016. (Photo by Bassam Khabieh/Reuters)





A general view shows the damage at a site hit by an airstrike in Kafr Jales village, north of Idlib City, Syria November 17, 2016. (Photo by Ammar Abdullah/Reuters)





People inspect the damage at a site hit by an airstrike in Kafr Jales village, north of Idlib City, Syria November 17, 2016. (Photo by Ammar Abdullah/Reuters)





Syria Democratic Forces (SDF) fighters stands near the damaged bridge of Balikh river near the town of Tel al-Saman in the northern rural area of Raqqa, Syria November 17, 2016. (Photo by Rodi Said/Reuters)





A Syria Democratic Forces (SDF) fighter carries binoculars as his fellow fighters walk near the town of Tel al-Saman in the northern rural area of Raqqa, Syria November 17, 2016. (Photo by Rodi Said/Reuters)





Syria Democratic Forces (SDF) fighters stand near the town of Tel al-Saman in the northern rural area of Raqqa, Syria November 17, 2016. (Photo by Rodi Said/Reuters)





Syria Democratic Forces (SDF) fighters carry their weapons as they walk near the town of Tel al-Saman in the northern rural area of Raqqa, Syria November 17, 2016. (Photo by Rodi Said/Reuters)





Syria Democratic Forces (SDF) fighters carry their weapons as they walk at a pumping station near the town of Tel al-Saman in the northern rural area of Raqqa, Syria November 17, 2016. (Photo by Rodi Said/Reuters)





A boy salvages belongings at a site hit yesterday by airstrikes in the rebel held Douma neighborhood of Damascus, Syria November 18, 2016. (Photo by Bassam Khabieh/Reuters)





An injured man sits amid the damage at a site hit yesterday by airstrikes in the rebel held Douma neighborhood of Damascus, Syria November 18, 2016. (Photo by Bassam Khabieh/Reuters)





A man salvages belongings at a site hit yesterday by airstrikes in the rebel held Douma neighborhood of Damascus, Syria November 18, 2016. (Photo by Bassam Khabieh/Reuters)





Medics treat an injured child inside a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. (Photo by Abdalrhman Ismail/Reuters)





Injured boys react at a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. (Photo by Abdalrhman Ismail/Reuters)





An injured boy sits near a man as they warm themselves by a fire in a rebel held area of Aleppo, Syria November 18, 2016. (Photo by Abdalrhman Ismail/Reuters)





A man assists an injured woman inside a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. (Photo by Abdalrhman Ismail/Reuters)





A Syrian Democratic Forces (SDF) military vehicle drives in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A Syrian Democratic Forces (SDF) fighter feeds a puppy in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A Syrian Democratic Forces (SDF) female fighter boils a kettle while resting in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A Syrian Democratic Forces (SDF) fighter looks through the scope of his weapon in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





Syrian Democratic Forces (SDF) fighters walk in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A Syrian Democratic Forces (SDF) vehicle with a weapon installed on it is pictured, in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A Syrian Democratic Forces (SDF) female fighter rests in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A medic stands behind sandbags in the damaged al-Hakeem hospital, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. (Photo by Abdalrhman Ismail/Reuters)





A man removes broken glass from a damaged Civil Defence vehicle in the rebel-held besieged area of Aleppo, Syria November 19, 2016. (Photo by Abdalrhman Ismail/Reuters)





A Syrian Democratic Forces (SDF) female fighter's braid is pictured while she is carrying her weapon in Tal Samin village, north of Raqqa city, Syria November 19, 2016. (Photo by Rodi Said/Reuters)





A member of the Syrian Civil Defense, known as the White Helmets, guides a colleague to extinguish fire following a reported government airstrike on the rebel-held town of Douma, on the eastern outskirts of the capital Damascus, on November 17, 2016. Douma, the largest town in the Eastern Ghouta area with more than 100,000 residents, is surrounded and regularly shelled by regime forces. (Photo by Sameer Al-Doumy/AFP Photo)





Shirin, 25, a member of the Kurdish female Women' s Protection Units (YPJ) views the battlefield with binoculars from atop a house in the Syrian village of Mazraat Khaled, some 40 kms away from the Islamic State group' s (IS) de- facto capital of Raqa on November 9, 2016 The YPJ are female brigades fighting alongside male fighters of the Syrian Democratic Forces (SDF), the militia alliance supported by the United States in the offensive launched on November 5 to capture Raqa from IS jihadists. (Photo by Delil Souleiman/AFP Photo)





A Syrian woman carries a child while on the way from areas controlled by jihadists of the Islamic State (IS) group, en route to safety in areas held by by Kurdish-Arab Syrian Democratic Forces (SDF) alliance, on November 9, 2016, near the village of Mazraat Khaled, some 40 km away from the Islamic State group's (IS) de-facto capital of Raqa. (Photo by Delil Souleiman/AFP Photo)





A Syrian pro-government fighter looks on from his sniper nest in a building in Aleppo's western Minyan district on November 10, 2016. The Observatory said that regime forces earlier in the week had retook the Minyan district in the west from rebels. Aleppo has been divided between government control in the west and rebel control in the east since mid-2012, but in recent months regime troops have surrounded the east, laying siege to it. (Photo by George Ourfalian/AFP Photo)