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)

Two citizens splash hot water which is quickly frozen in the cold air on January 7, 2021 in Beijing, China. A strong cold wave sweeps across China as the Chinese capital Beijing recorded 19.5 Celsius below zero on 06 January morning, the lowest temperature since 1966, according to meteorological authorities. (Photo by Peng Yucai/VCG via Getty Images)

People watch plumes of smoke and ash rise from as Taal Volcano erupts Sunday January 12, 2020, in Tagaytay, Cavite province, outside Manila, Philippines. (Photo by Aaron Favila/AP Photo)

A child dressed in a Santa Claus costume reacts, on the day Palestinian Christians attend an Orthodox Christmas Mass at the Greek Orthodox Saint Porphyrius Church, amid the ongoing conflict between Israel and Hamas, in Gaza City on January 7, 2025. (Photo by Dawoud Abu Alkas/Reuters)

A woman wearing a protective mask walks outside a church in Mandaluyong, east of Manila, Philippines on Sunday, February 2, 2020. The Philippines on Sunday reported the first death of a new virus outside of China, where authorities delayed the opening of schools in the worst-hit province and tightened quarantine measures in another that allow only one family member to venture out to buy supplies. (Photo by Aaron Favila/AP Photo)

Bangladeshi Muslim devotees arrive in an over-crowded train to attend the final day of an Islamic congregations' first phase in Tongi, 20 kilometers (13 miles) north of Dhaka, Bangladesh, Sunday, January 10, 2016. The second phase of the annual event, one of the world's largest congregations of Muslims is scheduled to begin Friday. (Photo by A.M. Ahad/AP Photo)

Villagers riding a rickshaw maneuver along an overflowing dam at the border between Cavite province and Las Pinas city, in Las Pinas, Philippines, 25 October 2020. According to Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA), Typhoon Molave will make landfall in the evening of 25 October in southern Luzon island. An alert was issued to residents for possible floods and landslides. (Photo by Francis R Malasig/EPA/EFE)

Britain's Health and Social Care Secretary Matt Hancock wears Union Jack socks as he leaves with Britain's Leader of the House of Lords Baroness Evans after a cabinet meeting on Downing Street in London, Britain on January 7, 2020. (Photo by Toby Melville/Reuters)