A Syrian child eats candy floss while selling it on a street cart in the Syrian city of al- Bab in the northern Aleppo province on May 15, 2017. (Photo by Zein Al Rifai/AFP Photo)





Members of the Syrian Democratic Forces (SDF), made up of an alliance of Kurdish and Arab fighters, stand some two kilometres from the Al- Meshleb neighbourhood of Raqa as they try to advance further into the Islamic State (IS) group' s Syrian bastion, on June 7, 2017 two days after finally entering the northern city. The SDF alliance began the battle for the city earlier this week after seven months of fighting to surround the key jihadist stronghold. (Photo by Delil Souleiman/AFP Photo)





A man surveys damage at the mountain resort town of Zabadani in the Damascus countryside, Syria, on Thursday, May 18, 2017. An estimated 400,000 have been killed and half the population displaced by the 6-year-old civil war. (Photo by Hassan Ammar/AP Photo)





Smoke rises from buildings following a reported air strike on a rebel-held area in the southern Syrian city of Daraa, on May 22, 2017. (Photo by Mohamad Abazeed/AFP Photo)





Syrians, who fled the Islamic State (IS) group stronghold of Raqa, in an area near the village of Balaban, south of Jarablus on June 7, 2017. (Photo by Zein Al Rifai/AFP Photo)





Parkour coach Ibrahim al-Kadiri (R), 19, and Muhannad al-Kadiri, 18, demonstrate their Parkour skills amid damaged buildings in the rebel-held city of Inkhil, west of Deraa, Syria, April 7, 2017. Ibrahim discovered Parkour in Jordan, where he had fled to escape the war. Back in his home town since 2015, he now leads a group of 15 practitioners. (Photo by Alaa Al-Faqir/Reuters)





A man gestures at U.S military vehicles driving in the town of Darbasiya next to the Turkish border, Syria April 28, 2017. (Photo by Rodi Said/Reuters)





Relief workers unload humanitarian aid in the rebel-held besieged Syrian town of Douma, Damascus, Syria May 3, 2017. (Photo by Bassam Khabieh/Reuters)





Internally displaced people who fled Raqqa city carry their belongings as they leave a camp in Ain Issa, Raqqa Governorate, Syria May 4, 2017. (Photo by Rodi Said/Reuters)





An internally displaced Syrian girl who fled Raqqa city carries a bag on her head inside a camp in Ain Issa, Raqqa Governorate, Syria May 2, 2017. (Photo by Rodi Said/Reuters)





Abu Fahad (2nd R) rests with colleges inside a workshop in the rebel-held besieged Douma neighbourhood of Damascus, Syria April 1, 2017. The workshop uses plastic from bottles and other waste materials to produce liquid and gas fuels.The liquid is refined into gasoline, diesel and benzene fuels which are sold for domestic and commercial use. (Photo by Bassam Khabieh/Reuters)





Internally displaced people who fled Raqqa city ride a vehicle in a camp near Ain Issa, Raqqa Governorate, Syria May 19, 2017. (Photo by Rodi Said/Reuters)





People celebrate carrying a Russian and Syrian national flags inside Waer district, after rebel fighters and their families evacuated the besieged Waer district in the central Syrian city of Homs, after an agreement was reached between rebels and Syria's army, Syria May 21, 2017. (Photo by Omar Sanadiki/Reuters)





Rebel fighters carry their weapons and belongings as they talk to a Syrian army soldier, as rebel fighters and their families evacuate the besieged Waer district in the central Syrian city of Homs, after an agreement was reached between rebels and Syria's army, Syria May 21, 2017. (Photo by Omar Sanadiki/Reuters)





A boy sits outside a shop in the rebel held besieged eastern Damascus suburb of Ghouta, Syria May 24, 2017. (Photo by Bassam Khabieh/Reuters)





Schoolchildren learn how to protect themselves in case of a bombardment during a war safety awareness class as part of a campaign conducted by the Syrian civil defence, known as The White Helmets, in the rebel-held area of Harasta, on the northeastern outskirts of the capital Damascus, on May 2, 2017. (Photo by Sameer Al-Doumy/AFP Photo)





A boy carries raw pastries prior to baking, to be sold during Ramadan in the rebel held besieged eastern Damascus suburb of Ghouta, Syria May 28, 2017. (Photo by Bassam Khabieh/Reuters)





This photo provided by Azaz Media Office, a Syrian anti-government activist group, which has been authenticated based on its contents and other AP reporting, shows a Syrian White Helmet civil defense worker extinguishing a burning car at the explosion scene, in Azaz town, north Syria, Wednesday, May 3, 2017. Syrian activists say a large explosion in a northern town along the border with Turkey has killed and wounded several people. (Photo by Azaz Media Office via AP Photo)





In this photo taken on Tuesday May 23, 2017, provided by the Syrian anti-government activist group, the Hammurabi's Justice News, which has been authenticated based on its contents and other AP reporting, shows a U.S.-backed anti-government Syrian fighter form Maghaweer al-Thawra stands on a vehicle with heavy automatic machine gun, left, next of an American soldier who also stands on his armored vehicle, right, as they take their position at the Syrian-Iraqi crossing border point of Tanf, south Syria. (Photo by Hammurabi's Justice News via AP Photo)





In this May 18, 2017. photo, a Syrian checks her mobile as others dance at a popular bar in the Old City in Damascus, Syria, Across the capital, new shops are sprouting up, business is brisk, and some people who fled the war years ago are contemplating a return. The Syrian civil war is likely to drag on for years, but in the seat of President Bashar Assad’s government, there is a general feeling that the six-year conflict is winding down. (Photo by Hassan Ammar/AP Photo)





In this May 18, 2017 file photo, Syrian boys pose for a picture as they sell balloons at the Hamadiyah market, in the Old City of Damascus, Syria. Across the capital, new shops are sprouting up, business is brisk, and some people who fled the war years ago are contemplating a return. The Syrian civil war is likely to drag on for years, but in the seat of President Bashar Assad’s government, there is a general feeling that the six-year conflict is winding down. (Photo by Hassan Ammar/AP Photo)





In this May 18, 2017 photo, a car passes by damaged streets at the mountain resort town of Zabadani in the Damascus countryside, Syria. Once a popular summer resort famed for its fruit trees and favored by tourists from rich Gulf Arab countries, the Damascus suburb town of Zabadani is now a deserted, endless vista of pulverized buildings after thousands of rebels were driven out along with the town’s original inhabitants. (Photo by Hassan Ammar/AP Photo)





In this May 18, 2017 photo, Fayez Ghosn surveys damage in his house at the mountain resort town of Zabadani in the Damascus countryside, Syria. (Photo by Hassan Ammar/AP Photo)





Smoke billows following a reported air strike on a rebel-held area in the southern Syrian city of Daraa early on June 9, 2017. (Photo by Mohamad Abazeed/AFP Photo)





A member of the US-backed Syrian Democratic Forces (SDF), made up of an alliance of Arab and Kurdish fighters, splashes water at the Tabqa dam on April 29, 2017, which has been recently partially recaptured, as part of their battle for the Islamic State's (IS) stronghold in nearby Raqa. The Syrian Democratic Forces now control at least 40 percent of the town of Tabqa, and more than half of its heart, the Old City, the Syrian Observatory for Human Rights monitor said. (Photo by Delil Souleiman/AFP Photo)





A little girl holding her newborn sister waits for their turn in a queue during a vaccination campaign under the supervision of the Syrian Arab Red Crescent (SARC) humanitarian nonprofit organization, in the besieged Syrian town of Douma, Syria, 23 May 2017. According to a statement from SARC, in the city of Douma some 12,809 children under the age of five were immunized in a vaccination campaign to prevent measles and poliomyelitis. The campaign was the first of its kind with the participation of 100 volunteers. SARC has been delivering vaccines to 17 health centers approved for vaccination campaigns in towns and villages in the Eastern Ghouta area. (Photo by Mohammed Badra/EPA)