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)

Spain’s fans react after their team lost the match against Italy while watching the match in a bar during the Euro 2020 soccer championship semifinal match between Italy and Spain, in Pamplona, northern Spain, Tuesday, July 6, 2021. (Photo by Alvaro Barrientos/AP Photo)

Nina Betschart of Team Switzerland dives against Germany during the Women's Preliminary - Pool F on day one of the Tokyo 2020 Olympic Games at Shiokaze Park on July 24, 2021 in Tokyo, Japan. (Photo by Sean M. Haffey/Getty Images)

Kubra Korkut of Turkey in action against Viktoriia Safonova of the Russian Paralympic Committee during Class 7 Group B Women's Singles Table Tennis Match on day 2 of the Tokyo 2020 Paralympic Games at Tokyo Metropolitan Gymnasium on August 26, 2021 in Tokyo, Japan. (Photo by Ivan Alvarado/Reuters)

Souvenirs seller smiles during the street market of the “2021 Agrorus” international agricultural fair at the Expoforum exhibition centre in St. Petersburg, Russia, 02 September 2021. The Exhibition opens for visitors until 05 September 2021. (Photo by Anatoly Maltsev/EPA/EFE)

An Indian girl wearing traditional attire takes selfie as others perform the Garba, a dance of Gujarat state, to celebrate the Hindu festival Navratri in Ahmedabad, India, Thursday, October 7, 2021. Navratri, or nine nights festival, began Thursday. (Photo by Ajit Solanki/AP Photo)

A light installation called “Run Beyond” by Angelo Bonello is seen on the launch day of the Light Festival at Battersea Power station on January 13, 2022 in London, England. Running from January 13 to February 27, the curated collection of installations includes work by six artists, with two displays making their UK exhibition debut. (Photo by Leon Neal/Getty Images)