Israeli soldiers play the parts of wounded civilians during a drill simulating a toxic spill from an attack on a train in Beersheba, southern Israel, 13 January 2016, as Home Front medical teams, fire fighters and police carry out rescue operations. The large scale drill is the concluding exercise of the Fourth International Conference on Healthcare System Preparedness and Response to Emergencies and Disasters and includes some 200 of the world's experts on health system readiness from around the world. The conference is dealing with all types of medical emergencies from terrorist attacks to natural disasters. (Photo by Jim Hollander/EPA)

Rescue workers try to pull out a piece of an exploded Grad missile outside an apartment building in Vostochniy district of Mariupol, Eastern Ukraine, Sunday, January 25, 2015. Indiscriminate rocket fire slammed into a market, schools, homes and shops Saturday in Ukraine's southeastern city of Mariupol, killing at least 30 people, authorities said. The Ukrainian president called the blitz a terrorist attack and NATO and the U.S. demanded that Russia stop supporting the rebels. (Photo by Evgeniy Maloletka/AP Photo)

Anti-balaka militia originally sprang up to protect the Christian population of the Central African Republic, but now stand accused of human rights abuses themselves. Last month, the African Union branded militia targeting Muslims in Central African Republic as “terrorists” and said they would be treated as enemy combatants, a day after killing a Congolese peacekeeper and amid deepening international frustration at continuing violence in the impoverished and landlocked country. Photo: A female member of the anti-balaka, a Christian militia, patrols with other militiamen outside village of Zawa April 8, 2014. (Photo by Goran Tomasevic/Reuters)

On September 1, 2004, Chechen militants stormed an elementary school in the town of Beslan in the Russian republic of North Ossetia. They took 1,100 teachers, children, and their relatives hostage, demanding the withdrawal of federal forces from Chechnya as a condition for their release. On September 3, 2004, Russian security forces stormed the building, resulting in a battle in which more than 330 hostages died, including 186 children. Here: A man assists two young hostages who managed to escape from the school building after special forces entered the school in Beslan, North Ossetia, Friday 03 September 2004. (Photo by Yuri Kochetkov/EPA)

Police officers clear the area near Borough market at London Bridge on June 3, 2017 in London, England. Police have responded to reports of a van hitting pedestrians on London Bridge in central London. (Photo by Dan Kitwood/Getty Images)

New York Police Department tactical police officers stand guard near the New York Stock Exchange on September 9, 2011 in New York City. Officials are stepping up security in New York and Washington D.C. a day after U.S. officials received a credible but unconfirmed terror threat to utilize car bombs on bridges or tunnels in New York or Washington. (Photo by Justin Sullivan/Getty Images)

People mourn at a makeshift memorial in front of the Russian embassy in Yerevan on March 23, 2024, a day after a gun attack on the Crocus City Hall in Russia's Krasnogorsk. Camouflaged assailants opened fire at the packed Crocus City Hall in Moscow's northern suburb of Krasnogorsk on March 22, 2024, evening ahead of a concert by Soviet-era rock band Piknik in the deadliest attack in Russia for at least a decade. Russia on March 23, 2024, said it had arrested 11 people – including four gunmen – over the attack on a Moscow concert hall claimed by Islamic State, as the death toll rose to 133 people. (Photo by Karen Minasyan/AFP Photo)