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)

People who fled the violence from Islamic State-controlled northern Syrian town of al-Bab arrive in the rebel-held outskirts of the town, Syria February 3, 2017. (Photo by Khalil Ashawi/Reuters)

Syrians gather during an evacuation operation of rebel fighters and their families from rebel-held neighbourhoods on December 15, 2016 in the embattled city of Aleppo. A convoy of ambulances and buses left rebel territory in Aleppo in the first evacuations under a deal for opposition fighters to leave the city after years of fighting. The rebel withdrawal will pave the way for President Bashar al-Assad's forces to reclaim complete control of Syria's second city, handing the regime its biggest victory in more than five years of civil war. (Photo by Karam Al-Masri/AFP Photo)

Migrants prepare their food outside shelters in a muddy field called the Grande-Synthe jungle, near Dunkirk, northern France, January 12, 2016. The Grande-Synthe jungle is a camp of tents and makeshift shelters where migrants and asylum seekers from Irak, Kurdistan and Syria gather. (Photo by Benoit Tessier/Reuters)

Chahad, 16, gets groomed at a beauty Salon in Kalak before her wedding party, Iraq February 16, 2017. It's the second marriage to take place in the IDP camps east of the city where tens of thousands are living, having fled the fighting in Mosul. (Photo by Zohra Bensemra/Reuters)

32 year old Mahada Khatum repairs a fishing net outside her home in the Shamalapur Rohingya refugee settlement on April 11, 2014 in Chittagong district, Bangladesh. Some years ago she escaped violence and discrimination from the Zomgara Baharchara village in the Meherulla district of Myanmar. (Photo by Getty Images/Stringer)

Iraqi Kurdish refugees wait with children in Cukurca refugee camp in Turkey April 8, 1991. Reuters photographers have chronicled Kurdish refugee crises over the years. In 1991 Srdjan Zivulovic documented refugees in Cukurca who had escaped a military operation by Saddam Hussein's government in Iraq aimed at “Arabising” Kurdish areas in the north. Hundreds of thousands fled into Turkey and Iran. Images shot in recent months show familiar scenes as crowds of people flee Islamic State militants in Syria. There are as many as 30 million Kurds, spread through Turkey, Iraq, Syria and Iran. Most Kurds are Sunni Muslims, but tend to feel more loyalty to their Kurdishness, rather than their religion. (Photo by Srdjan Zivulovic/Reuters)

A Swiss police officer accompanies a migrant from Syria carrying her baby, upon her arrival at the railway station in the north-eastern Swiss town of Buchs September 1, 2015. (Photo by Arnd Wiegmann/Reuters)