Serbian police officers of the Special Anti-Terrorist Unit pose for a picture in their base outside Belgrade October 8, 2014. When the killing of an unarmed black teenager by a white policeman in Ferguson, Missouri, in August sparked sometimes violent protests, the response of police in camouflage gear and armoured vehicles wielding stun grenades and assault rifles seemed more like a combat operation than a public order measure. Some U.S. police departments have recently acquired U.S. military-surplus hardware from wars abroad, but there are many law enforcers around the world whose rules of engagement also allow the use of lethal force with relatively few restrictions. But for every regulation that gives police wide scope to use firearms, there is another code that sharply limits their use. In Serbia, police may use measures ranging from batons to special vehicles, water cannon and tear gas on groups of people who have gathered illegally and are behaving in a way that is violent or could cause violence, but they may use firearms only when life is endangered. (Photo by Marko Djurica/Reuters)

A Russian peacekeeper shouts “No pictures!” at a checkpoint outside the city of Stepanakert on November 13, 2020, during a ceasefire in the military conflict between Armenia and Azerbaijan over the breakaway region of Nagorno-Karabakh. Russian began deploying 2,000 peacekeepers to Nagorno-Karabakh on November 10 after Armenia and Azerbaijan agreed a peace deal to end weeks of fierce fighting over the disputed region. (Photo by Alexander Nemenov/AFP Photo)

A shopper gets caught in a heavy downpour of rain on Oxford Street, London on June 27, 2020, as sunshine and showers are forecast for much of England and Wales on Saturday, with temperatures expected to hover around 22°C (71.6F). (Photo by Dominic Lipinski/PA Images via Getty Images)

The Euro sculpture is partially reflected in a puddle on a cobblestone pavement in front of the headquarters of the European Central Bank in Frankfurt on Jan. 21. (Kai Pfaffenbach/Reuters)

A girl attends a performance hosted by the Ministry of the Interior that includes police, border guards, and rescuers celebrating International Children's Day in Kyiv, Ukraine on June 1, 2021. (Photo by Gleb Garanich/Reuters)

A man crosses a mud-covered trail carrying his wife on his back at a flooded Han River park in Seoul, South Korea, August 4, 2020. (Photo by Kim Hong-Ji/Reuters)

The space shuttle Endeavour is transported to the California Science Center in Exposition Park from Los Angeles International Airport (LAX) in Los Angeles, California. (Photo by Kevork Djansezian)

A woman from the Pataxo tribe poses for a photo at an indigenous protest camp on the fourth day of the Terra Livre Indigenous Camp in Brasilia on April 7, 2022. The 10-day annual protest is held by indigenous people from tribes that arrive from all over Brazil, and calls for greater protection of their land and rights. (Photo by Carl de Souza/AFP Photo)