Internally displaced Syrian children stand at the entrance of their makeshift shelter that is an underground cave in Om al-Seer, southern Idlib countryside, Syria December 26, 2015. (Photo by Khalil Ashawi/Reuters)

A man covered with dust sits on a street following a reported air strike by Syrian government forces in the rebel-held neighbourhood of Sukkari in the northern city of Aleppo on May 30, 2016. (Photo by Baraa Al-Halabi/AFP Photo)

A Palestinian youth practices his parkour skills at Shati refugee camp in Gaza City April 27, 2014. (Photo by Mohammed Salem/Reuters)

An internally displaced Afghan girl plays near their shelter at a refugee camp in Kabul January 13, 2015. (Photo by Omar Sobhani/Reuters)

North Kenya, Liboi. A young Somali refugee crosses a field filled with marabous storks in July 1992. (Photo by Jean-Claude Coutausse)

Syrian government troops patrol the newly captured al- Sakhour neighbourhood in the eastern part of the northern city of Aleppo on December 7, 2016 Rebels in Aleppo called for a five- day truce and the evacuation of civilians Wednesday after losing more than three quarters of their territory including the Old City to a Syrian army offensive. (Photo by George Ourfalian/AFP Photo)

Newly-wed Syrian couple Nada Merhi, 18, and Hassan Youssef, 27, have their wedding pictures taken in front of a heavily damaged building in the war ravaged city of Homs on February 5, 2016. A Syrian photographer thought of using the destruction of Homs to take pictures of newly wed couples to show that life is stronger than death. (Photo by Joseph Eid/AFP Photo)

Actors wearing masks of Syrian President Bashar al-Assad and Russian Prime Minister Vladimir Putin perform with body bags during a demonstration outside United Nations headquarters on January 24, 2011 in New York City. Protesters called on the U.N. Security Council to pass a resolution to attempt to halt al-Assad's crackdown on the Syrian uprising. (Photo by Mario Tama/Getty Images)