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)

This photo taken November 10, 2015 shows homeless street children sleeping in a park in Manila. The Philippines has swept 20,000 homeless from the streets, cancelled hundreds of flights and declared public holidays in Manila to ensure a safe and efficient summit of 21 world leaders next week, officials say. (Photo by Jay Directo/AFP Photo)

A ballet dancer stretches backstage during Nacho Duato's “The Nutcracker” at the Mikhailovsky Theatre in St. Petersburg, Russia November 21, 2015. For theatregoers in St Petersburg, Nacho Duato's “The Nutcracker” demonstrates the global appeal of a Christmas classic. When the curtain rises at the Mikhailovsky Theatre, among the oldest opera and ballet houses in Russia, it's the culmination of hundreds of hours of toil and sweat by dancers, costume makers, set designers and musicians playing the famous score by Pyotr Tchaikovsky. (Photo by Grigory Dukor/Reuters)

Models walk the runway for Sergio Hudson during New York Fashion Week: The Shows at Spring Studios on February 13, 2022 in New York City. (Photo by Noam Galai/Getty Images for NYFW: The Shows)

A Ukrainian serviceman fires with a ZU-23-2 anti-aircraft cannon at a position near a front line in the Kharkiv region, as Russia's attack on Ukraine continues, Ukraine on August 10, 2022. (Photo by Vyacheslav Madiyevskyy/Reuters)

A resident (unseen) uses a belt to get vegetables in Wuhan, in China's central Hubei province on March 13, 2020. China reported just eight cases of the coronavirus on March 13, with no new domestic infections outside the epicentre of Hubei province. (Photo by AFP Photo/China Stringer Network)

Thai dancers use face shield while waiting for worshippers, after the government eased some coronavirus restrictions, at the Erawan shrine, a popular tourists site, in Bangkok, Thailand, 03 May 2020. The Thai government announced that some businesses and shops can reopen and services and some activities can be resumed from 03 May 2020 on as long as social distancing and regulations are in place. (Photo by Narong Sangnak/EPA/EFE/Rex Features/Shutterstock)

A resident brings his dog that uses a mask in Jakarta, Indonesia, on May 12, 2020. (Photo by Jefta Images/Barcroft Media via Getty Images)