Internally displaced Syrians who fled Raqqa tie ropes for their tents in a camp in Manbij, Syria on April 6, 2017. (Photo by Rodi Said/Reuters)

Aisha, 15, (L) (who asked to withhold her last name), a Syrian refugee from Raqqa, waits with a fellow refugee while harvesting cannabis in the Bekaa valley, Lebanon October 19, 2015. Syrian refugees work to harvest and process spiky-leafed cannabis plants in neighbouring Lebanon’s Bekaa Valley. Often farmers of cotton and wheat back home in Raqqa province – now the de facto capital of Islamic State – the conflict in Syria drove them to seek safety in a region where Syrian migrant workers used to spend a few months a year before returning home. (Photo by Alia Haju/Reuters)

This Wednesday, August 31, 2016 photo, provided by the Syrian anti-government activist group Aleppo Media Center (AMC), shows Syrian boys dive into a hole filled with water that was caused by a missile attack in the rebel-held neighborhood of Sheikh Saeed in Aleppo province, Syria. (Photo by Aleppo Media Center via AP Photo)

A boy looks back while he and another boy play on a Syrian military tank, destroyed during fighting with the Rebels, in the Syrian town of Azaz, on the outskirts of Aleppo, Sunday, September 2, 2012. (Photo by Muhammed Muheisen/AP Photo)

Girls cry as they get separated from their family at the border line dividing Macedonia and Greece August 21, 2015. At least 1,000 migrants and refugees pressed against Macedonian police lines on the Greek-Macedonian border on Friday and at least 10 people appeared to faint in the crush. People could be heard screaming and medical workers raced to treat those who passed out or were hurt. The crush ensued after police let several hundred through into Macedonia, having kept them out since Thursday under an emergency decree. (Photo by Ognen Teofilovski/Reuters)

Families and relatives of the dead cry as they identify their family members at a temporary burial ground March 25, 2011 in Higashi Matsushima , Japan. (Photo by Paula Bronstein /Getty Images)

A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)

Malawian Saw-wa, 33, (L) and Yupin Saw-wa, 28 who lost their daughters, cry near a burnt building at the Pitakkiat Wittaya School in the northern province of Chiang Rai, Thailand, May 23, 2016. (Photo by Athit Perawongmetha/Reuters)