In this photo taken on Wednesday, February 17, 2016, a volunteer fighter with the Syrian Government forces sits atop a tank in the province of Raqqa, Syria. In recent weeks, Syrian government forces captured dozens of villages and towns across the country. (Photo by Alexander Kots/Komsomolskaya Pravda via AP Photo)

A child coughs as migrants and refugees run away after Macedonian police fired tear gas at hundreds of Iraqi and Syrian migrants who tried to break through the Greek border fence in Idomeni, on February 29, 2016. Greek police said more than 6,000 people were massed at the border, in a buildup triggered by Austria and Balkan states capping the numbers of migrants entering their territory. (Photo by Louisa Gouliamaki/AFP Photo)

Dancer Chachi Gonzalez arrives at Nickelodeon's 2016 Kids' Choice Awards in Inglewood, California March 12, 2016. (Photo by Mario Anzuoni/Reuters)

Figure Skating, ISU World Figure Skating Championships, Ladies Short Program, Boston, Massachusetts, United States on March 31, 2016: Ashley Wagner of the United States stumbles and falls while celebrating after competing. (Photo by Brian Snyder/Reuters)

A woman cries after a supporter of opposition leader Raila Odinga was killed by police, witnesses said, in Mathare slum in Nairobi, Kenya August 9, 2017. (Photo by Goran Tomasevic/Reuters)

Models pose backstage ahead of the Zhivago show at Mercedes-Benz Fashion Week Resort 17 Collections at Carriageworks on May 16, 2016 in Sydney, Australia. (Photo by Mark Nolan/Getty Images)

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)

A student aims a stick of wood at Bolivarian National Police officers during clashes outside the Central University in Caracas, Venezuela, Thursday, June 9, 2016. Students had planned to march from Venezuela's top university to elections headquarters, but hundreds of police in riot gear blocked the way. Students covered their faces with Venezuelan flags and threw bottles, stones and sticks while police lobbed tear gas. (Photo by Fernando Llano/AP Photo)