South Korean rescue members wearing chemical protective suits walk past a monster character (R) during an anti-terror drill as part of a disaster management exercise at the COEX shopping and exhibition center in Seoul on May 20, 2016. South Korea is holding its 2016 Safe Korea anti-disaster exercise this week against terrorist threats and natural disasters. (Photo by Jung Yeon-Je/AFP Photo)

Iraqi pro-government forces fire an anti-tank cannon near al-Sejar village, north-east of Fallujah, on May 25, 2016, as they take part in a major assault to retake the city from the Islamic State (IS) group. Iraqi forces, consisting of special forces, soldiers, police, paramilitary-fighters and pro-government tribesmen, launched a major assault to retake Fallujah, the scene of deadly battles during the US occupation and one of the toughest targets yet in Baghdad's war on the Islamic State group. (Photo by Ahmad Al-Rubaye/AFP Photo)

Baker Magadma, a member of Palestinian sports group Bar Palestine, performs on the street in Gaza City, on June 3, 2016. Street workout, which is still new in Gaza, is a growing sport across the world with annual competitions and events. (Photo by Mohammed Abed/AFP Photo)

Sandra Brown, 40, rides the Skyslide on the 69th and 70th floors of the U.S. Bank Tower which is attached to the OUE Skyspace LA observation deck in downtown Los Angeles, California, U.S. June 20, 2016. (Photo by Lucy Nicholson/Reuters)

A man impersonating Kim Jong-un gestures during the athletics at the Rio 2016 Olympic Games at the Olympic Stadium in Rio de Janeiro on August 18, 2016. (Photo by Johannes Eisele/AFP Photo)

A woman offers a prayer at Pashupatinath Temple during the Teej festival in Kathmandu, Nepal September 4, 2016. During this festival, married Hindu women observe day-long fast and pray for a happy married life while those unmarried pray for a good husband. (Photo by Navesh Chitrakar/Reuters)

A Houthi follower with fake blood on his clothes lies on the ground to represent a victim as others perform a war dance during a ceremony marking the first anniversary of the Houthi movement's takeover of Yemen's capital Sanaa September 21, 2015. (Photo by Khaled Abdullah/Reuters)

Paramilitary policemen take part in a training in Chaohu, Anhui province, China December 28, 2015. (Photo by Reuters/China Daily)