Civilians, who fled the violence in Manbij city, arrive to the southeastern rural area of Manbij, in Aleppo Governorate, Syria June 19, 2016. (Photo by Rodi Said/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)

Syrian Internal Security Forces dance in celebration during their graduation ceremony, at Ain Issa desert base, in Raqqa province, northeast Syria, Thursday, July 20, 2017. Some 250 residents of Syria's Raqqa province are the latest batch to graduate from a brief U.S-training course that is preparing an internal security force to hold and secure areas as they are captured from Islamic State militants. (Photo by Hussein Malla/AP Photo)

In this Tuesday, March 17, 2015 photo, a French military plane takes off from the flight deck of the French Navy aircraft carrier Charles de Gaulle in the Persian Gulf. Aircraft aboard the French carrier are flying bombing and reconnaissance missions as part of a U.S.-led coalition targeting Islamic State militants in Iraq. (Photo by Hasan Jamali/AP Photo)

Breitling Wingwalkers aircrafts perform during an aerobatic display at an air show in Zhengzhou, Henan province, China, September 25, 201. (Photo by Reuters/Stringer)

Children attend a war safety awareness class conducted by civil defence members, in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria May 14, 2016. (Photo by Khalil Ashawi/Reuters)

One of the poor families collecting firewood from the street and the burn to feel some warmth in Aleppo, Syria on August 19, 2016. (Photo by Basem Ayoubi/Imageslive/ZUMA Press/Splash News)

Women walk past a mannequin with a covered face as they shop ahead of the Muslim festival of Eid-al-Adha in Aleppo, Syria September 23, 2015. (Photo by Hamid Khatib/Reuters)