A wounded protester is attended before being rushed to a vehicle following violence in Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by Konstantin Chernichkin/Reuters)

Riot police officers in position to crack down on demonstrators during a protest against Venezuelan President Nicolas Maduro, in Caracas on April 20, 2017. Venezuelan riot police fired tear gas Thursday at groups of protesters seeking to oust President Nicolas Maduro, who have vowed new mass marches after a day of deadly unrest. Police in western Caracas broke up scores of opposition protesters trying to join a larger march, though there was no immediate repeat of Wednesday's violent clashes, which left three people dead. (Photo by Juan Barreto/AFP Photo)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. Serbian league leaders Partizan Belgrade held champions and bitter city foes Red Star to a 0-0 draw in a derby match marred by bad crowd trouble before kickoff on Saturday. The start was delayed for 45 minutes after home Red Star supporters pelted riot police with seats and flares, forcing officers to retreat from the north tier that houses the club's diehard fans. (Photo by Marko Djurica/Reuters)

Riot police scuffle with pro-democracy students after hundreds of protesters stormed into a restricted area at the government headquarters, after a rally ahead of the October 1 “Occupy Central” civil disobedience movement in Hong Kong September 27, 2014. Hong Kong riot police used pepper spray on Saturday to disperse dozens of students who had stormed government headquarters, but an equal number held their ground in protests against Beijing's tightening grip on the city. (Photo by Tyrone Siu/Reuters)

Russian riot policemen beat young PREGNANT female anti-Putin activist during a protest rally against the Presidential inauguration of Vladimir Putin on May 6, 2012 in Moscow, Russia.

An anti-government protester wearing a Guy Fawkes mask stands with a shield near flames from molotov cocktails thrown at a water cannon by anti-government protesters during riots in Caracas in this April 20, 2014 file photo. (Photo by Jorge Silva/Reuters)

A demonstrator dressed as Santa Claus holds up a flag as a riot police vehicle releases a jet of water during a protest against the private system of pension fund administrators in Santiago, Chile, December 10, 2015. The flag reads “Classist Workers Union”. (Photo by Ivan Alvarado/Reuters)

People take cover as riot police use pepper spray projectile during a protest as a second reading of a controversial national anthem law takes place in Hong Kong, China on May 27, 2020. (Photo by Tyrone Siu/Reuters)