A rescue worker holds an injured boy after what activists said were airstrikes carried out by the Russian air force in Idlib city, Syria December 20, 2015. (Photo by Ammar Abdullah/Reuters)

A Syrian youth Khaled from Raqqa walks on snow wearing slippers in the Bekaa Valley refugee camp in Lebanon after the first heavy snow storm hit Lebanon, January 3, 2016. (Photo by Jamal Saidi/Reuters)

Cattle keepers from the Dinka tribe perform a traditional dance after a prayer session for peace and good health along the route to Rajaf Payam outside the capital Juba October 18, 2014. (Photo by Jok Solomon/Reuters)

Hindu women apply “sindhur”, or vermillion powder, on the face of a woman after worshipping the idol of the Hindu goddess Durga on the last day of the Durga Puja festival in Chandigarh, India October 11, 2016. (Photo by Ajay Verma/Reuters)

People run in panic after a coalition airstrike hit Islamic State fighters positions in Tahrir neighbourhood of Mosul, Iraq, November 17, 2016. (Photo by Goran Tomasevic/Reuters)

People look at damaged trees after a tornado hit Funing on Thursday, in Yancheng, Jiangsu province, China June 24, 2016. (Photo by Aly Song/Reuters)

A man stands near bodies of his young relatives after an airstrike in the rebel held Douma neighbourhood of Damascus, Syria August 22, 2016. (Photo by Bassam Khabieh/Reuters)

Migrants storm into a train at the Keleti train station in Budapest, Hungary, September 3, 2015 as Hungarian police withdrew from the gates after two days of blocking their entry. (Photo by Laszlo Balogh/Reuters)