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)

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 Palestinian student jumps through a fire ring during a military-style show at a school in Rafah in the southern Gaza Strip March 28, 2016. (Photo by Ibraheem Abu Mustafa/Reuters)

People dressed as Hungarian Hussars fire a cannon during re-enactment of the battle against Austrian soldiers of the Habsburg dynasty in Tapiobicske, Hungary April 4, 2016. (Photo by Laszlo Balogh/Reuters)

An unidentified elderly woman, who was knocked over during the melee after a shot was fired in the direction of President Ford, is comforted by a passerby in San Francisco, September 23, 1975. (Photo by AP Photo)

The sky looked on fire this morning, as it made the clouds glow red, just before sunrise at Peterborough Rowing Lake, in Nene Park, UK on January 18, 2017. (Photo by Paul Marriott/Rex Features/Shutterstock)

A boy fires confetti poppers as he participates in a procession to mark Eid-e-Milad-ul-Nabi, the birthday celebration of Prophet Mohammad, in Mumbai January 4, 2015. (Photo by Danish Siddiqui/Reuters)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)