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)

Londoners enjoy a “Silent Night” as Big Ben falls silent, London, UK on August 21, 2017. ose Allerston from Clapham, London said “After a stressful day in the office, I couldn't think of anything better than going home and climbing into bed – but when I saw this bed opposite Big Ben I just couldn't resist getting in for a snuggle”. (Photo by Imagewise Ltd/Rex Features/Shutterstock)

A police officer detains a person during protest by supporters of Pakistan's former Prime Minister Imran Khan against his arrest, in Karachi, Pakistan, 09 May 2023. Khan, the chairman of Pakistan Tehreek-e-Insaf, was taken into custody by the National Accountability Bureau (NAB) on 09 May outside the Islamabad High Court, where he had arrived to appeal for bail in multiple cases filed against him. The arrest came after Khan's ouster from power in April 2020 following a failed vote of confidence in parliament. (Photo by Rehan Khan/EPA)

Pregnant Tibetan antelopes move across the Qinghai-Tibet highway in Hoh Xil, northwest China's Qinghai Province, May 29, 2023. A growing number of pregnant Tibetan antelopes are migrating to the heart of northwest China's Hoh Xil National Nature Reserve to give birth, according to the reserve's management office. Every year, tens of thousands of pregnant Tibetan antelopes start their migration to Hoh Xil in around May to give birth and leave with their offspring in late July. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

Russia's Darya Klishina prepares for the women's long jump qualification during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Tuesday, August 16, 2016. She might be feeling the pressure of being all alone, but Darya Klishina could yet still win Russia's only athletics medal at the Rio 2016 Games. (Photo by Matt Dunham/AP Photo)

A photograph made available on 30 September 2016 showing wind turbines at the site of the highest wind park in Europe at the Griessee, near the Nufenenpass in the Swiss south Alpes, Valais, Switzerland, on 23 September 2016. The four wind turbines of this wind park were developed by the company SwissWinds GmbH and are inaugurated on, 30 September 2016. (Photo by Olivier Maire/EPA)

Riot police fire tear gas during a protest by supporters of Dilma Rousseff in Sao Paulo, Brazil August 31, 2016. (Photo by Paulo Whitaker/Reuters)

A picture made available on 20 June 2016 shows people praying as they wait to break the fast during the Muslim holy month of Ramadan, in Karachi, Pakistan, 19 June 2016. Muslims around the world celebrate the holy month of Ramadan by praying during the night time and abstaining from eating and drinking during the period between sunrise and sunset. Ramadan is the ninth month in the Islamic calendar and it is believed that the Koran's first verse was revealed during its last 10 nights. (Photo by Shahzaib Akber/EPA)