Riot police fire tear gas at demonstrators during a protest against fare hikes for city buses in Sao Paulo, Brazil, January 8, 2016. Brazilian riot police on Friday fired tear gas and stun grenades to disperse a violent protest against a rise in public transport fares in the country's largest city, Sao Paulo. (Photo by Nacho Doce/Reuters)

A protester squirts a water gun at Catalan regional police in full riot gear during a protest over the eviction of squatters earlier in the week from “The Expropriated Bank”, in Barcelona, Spain, May 29, 2016. (Photo by Albert Gea/Reuters)

Members of security forces secure Tahrir Square in Cairo, Egypt, November 11, 2016. Egypt imposed a big security clampdown in its cities on Friday as mass demonstrations called to protest against austerity measures failed to take place. Riot police and armored vehicles filled the otherwise empty streets of central Cairo, but most people stayed at home. (Photo by Mohamed Abd El Ghany/Reuters)

Supporters of Honduran presidential candidate for the Opposition Alliance against the Dictatorship party Salvador Nasralla, are affected by tear gas during a protest outside the Electoral Supreme Court (TSE), to demand the announcement of the election final results in Tegucigalpa, on November 30, 2017. (Photo by Orlando Sierra/AFP Photo)

Men stand at the top of a traffic lights post as they attend a rally to protest against satirical cartoons of prophet Mohammad, in Grozny, Chechnya January 19, 2015. Tens of thousands of people staged the rally on Monday in Chechnya against French magazine Charlie Hebdo's cartoons of the prophet, which the predominantly Muslim region's leader denounced as “vulgar and immoral”. The posters read, “Mohammad”. (Photo by Eduard Korniyenko/Reuters)

Egyptian riot police charge towards protesters near Egypt's Interior Ministry, as violent demonstrations continued into their second day on February 3, 2012 in central Cairo, Egypt. (Photo by Ed Giles/Getty Images)

Punk protest band p*ssy Riot member Maria Alyokhina is detained by police at a protest in central Moscow February 24, 2014. Russian riot police detained over a hundred protesters, including two members of p*ssy Riot, on Monday at a Moscow courthouse where seven opponents of President Vladimir Putin were jailed from two and a half to four years over a demonstration that turned violent. (Photo by Maxim Shemetov/Reuters)

Wounded Reuters photographer Gleb Garanich, who was injured by riot police, takes pictures as riot police block protesters during a scuffle at a demonstration in support of EU integration at Independence Square in Kiev November 30, 2013. Riot police in the Ukrainian capital Kiev used batons and stun grenades to disperse hundreds of pro-Europe protesters from the city's main Independence Square early on Saturday, witnesses said. (Photo by Reuters/Stringer)