A Kurdish fighter from the People's Protection Units (YPG) fires his rifle at Islamic State militants as he runs across a street in Raqqa, Syria, July 2017. (Photo by Goran Tomasevic/Reuters)

Boys play with a ball in front of oilfields burned by Islamic State fighters in Qayyara, south of Mosul, Iraq November 23, 2016. (Photo by Goran Tomasevic/Reuters)

A tribal fighter loyal to Yemen's government stands in Al Khurais village of Nihm district east of the capital Sanaa January 11, 2016. (Photo by Ali Owidha/Reuters)

A crew members walks on the flight deck past Super Etendard fighter jets aboard France's Charles de Gaulle aircraft carrier on missino in the Gulf, January 29, 2016. (Photo by Philippe Wojazer/Reuters)

Rebel fighters from the Ahrar al-Sham Islamic Movement fire a heavy machine gun during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)

A female sniper of the Syrian Democratic Forces (SDF) monitors the area during a celebration at the iconic Al- Naim square in Raqa on October 19, 2017, after retaking the city from Islamic State (IS) group fighters. The SDF fighters flushed jihadist holdouts from Raqa' s main hospital and municipal stadium, wrapping up a more than four- month offensive against what used to be the inner sanctum of IS' s self- proclaimed “caliphate”. (Photo by Bulent Kilic/AFP Photo)

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)

NATO and U.S. flags flutter as U.S. Air Force F-22 Raptor fighter flies over the military air base in Siauliai, Lithuania, April 27, 2016. (Photo by Ints Kalnins/Reuters)