A man gets stuck under debris at a damaged site after an airstrike in the Saqba area, in the eastern Damascus suburb of Ghouta, Syria, January 9, 2018. (Photo by Bassam Khabieh/Reuters)

Guests brew coffee during a wedding ceremony for a Free Syrian Army fighter in the town of Douma, eastern Ghouta in Damascus, Syria January 19, 2016. (Photo by Bassam Khabieh/Reuters)

A man works inside a bakery in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria December 17, 2015. (Photo by Khalil Ashawi/Reuters)

Hadeel, 10, asks a passerby for help to pay a medical bill as her father Shahrour, 54, sits in his wheelchair in the Douma neighbourhood of Damascus Syria February 3, 2016. Shahrour said he developed diabetes at the beginning of the war in Syria. A lack of insulin led to his medical condition worsening and his right foot had to be amputated. Recently he also suffered a stroke that paralysed half his face. He and part of his extended family, a total of 18 people, live together and struggle to get by. (Photo by Bassam Khabieh/Reuters)

In this photo taken on Wednesday, February 17, 2016, a volunteer fighter with the Syrian Government forces sits atop a tank in the province of Raqqa, Syria. In recent weeks, Syrian government forces captured dozens of villages and towns across the country. (Photo by Alexander Kots/Komsomolskaya Pravda via AP Photo)

People carry drinks at 80s Bar in Damascus, Syria, March 11, 2016. In Damascus's Old City, just a mile from the battered frontline between government and rebel-held territory, young Syrians smoke, drink beer or soft drinks, and talk about anything but the war. The revival of activity in this once-vibrant quarter is part of efforts to project an air of normality in the Syrian capital, even as the five-year-old war that has killed more than 250,000 people and created 5 million refugees continues to rage nearby. (Photo by Omar Sanadiki/Reuters)

Five-year-old Ghazal al-Hussein poses inside a classroom in the rebel-controlled area of Maarshureen village in Idlib province, Syria March 12, 2016. March 15 marks the 5th anniversary of peaceful protests against Syria's President Bashar al-Assad, leading to the devastating civil conflict in the country. These are portraits of five-year-old Syrian children who have only known conflict in their country. (Photo by Khalil Ashawi/Reuters)