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)

A policewoman wipes her tears as she stands in front of metal caskets containing the bodies of Special Action Force (SAF) police who were killed in Sunday's clash with Muslim rebels, at Villamor Air Base in Pasay city, metro Manila January 29, 2015. Philippine President Benigno Aquino urged legislators on Wednesday not to abandon a plan for autonomy for Muslims to end a decades-old insurgency after the clash in which dozens of people were killed, saying doing so would dash hopes for peace. (Photo by Romeo Ranoco/Reuters)

In this April 20, 2017 photo, a woman is aided by fellow demonstrators after falling, overcome by tear gas, during anti-government protests in Caracas, Venezuela. Tens of thousands of protesters asking for the resignation of President Nicolas Maduro flooded the streets again, one day after three people were killed and hundreds arrested in the biggest anti-government demonstrations in years. (Photo by Ariana Cubillos/AP Photo)

A police officer pepper sprays a protester as another protester stands in front of the race director's car during a farmers' protest who attempted to block the stage' s route, during the 16 th stage of the 105 th edition of the Tour de France cycling race, between Carcassonne and Bagneres- de- Luchon, southwestern France, on July 24, 2018. The race was halted for several minutes on July 24 after tear gas was used as protesting farmers attempted to block the route. (Photo by Stephane Mahe/Reuters)

In this Wednesday, January 23, 2019, an anti-government protester covers her face with a Venezuelan flag, and uses toothpaste around her eyes to help lessen the effect of tear gas, during clashes with security forces after a rally demanding the resignation of President Nicolas Maduro in Caracas, Venezuela. The head of Venezuela's opposition-run congress declared himself interim president at the rally, until new elections can be called. (Photo by Fernando Llano/AP Photo)

Protesters run for cover after riot police fired tear gas towards the bridge they were climbing down to the road below, to escape from Hong Kong Polytechnic University campus and from police, in Hung Hom district in Hong Kong on November 18, 2019. Dozens of Hong Kong protesters escaped a besieged university campus on November 18 by lowering themselves on a rope from a footbridge to a highway, AFP video showed. Once on the road they were seen being picked up by waiting motorcyclists. (Photo by Anthony Wallace/AFP Photo)

A woman shouts asking for help during an eviction in Rio de Janeiro, Brazil, Friday, April 11, 2014. Squatters in Rio de Janeiro are clashing with police after a Brazilian court ordered that 5,000 people be evicted from abandoned buildings of a telecommunications company. Officers have used tear gas and stun grenades to try to disperse the families. (Photo by Silvia Izquierdo/AP Photo)

A woman who was injured after being trampled is helped away, after residents desperate for a planned distribution of food for those suffering under Kenya's coronavirus-related movement restrictions pushed through a gate and created a stampede, causing police to fire tear gas and leaving several injured, at a district office in the Kibera slum, or informal settlement, of Nairobi, Friday, April 10, 2020. (Photo by Brian Inganga/AP Photo)