Rebel fighters from the Jaish al- Fatah (or Army of Conquest) brigades manoeuver an alleged explosive- rigged make- shift armoured vehicle during a major assault on Syrian government forces West of Aleppo city on October 28, 2016 Syrian opposition fighters launched a major assault on government forces to break a months- long siege of rebel- held neighbourhoods of the battered city of Aleppo. Rebel groups including the powerful Ahrar al- Sham faction and former Al- Qaeda affiliate Fateh al- Sham Front fired waves of rockets into government- held western Aleppo, killing at least 15 civilians, a monitor said. (Photo by Omar Haj Kadour/AFP Photo)

School teachers and staff members take part during an active shooter training at James I. O'Neill High School in Highland Falls, New York, U.S., December 12, 2017. (Photo by Eduardo Munoz/Reuters)

Models struggle against strong wind before the rehearsal of Christian Dior's Haute Couture Spring-Summer 2017 live show to celebrate Dior's new flagship store on the rooftop of Ginza Six mall in Tokyo, Japan, April 19, 2017. (Photo by Toru Hanai/Reuters)

Police detain an alleged thief in Lagos' Tafawa Balewa Square where the official People's Democratic Party (PDP) opposition party is holding a rally on February 12, 2019. Nigerians will cast their ballots on February 16 in presidential and legislative elections. The presidential contest will see incumbent Muhammadu Buhari seek to win a second four-year term against former vice president Atiku Abubakar in what is expected to be a close race. (Photo by Luis Tato/AFP Photo)

In a photo taken on September 11, 2019, North Korean students pose for photos in Chonji lake, or “Heaven lake”, as they visit the crater of Mount Paektu, near Samjiyon. Mount Paektu has long been considered the spiritual birthplace of the Korean nation and is a place of pilgrimage for tens of thousands of North Koreans every year, who are trained from birth to revere their leaders. (Photo by Ed Jones/AFP Photo)

An injured national guard officer is carried away by comrades outside the parliament building in Kiev, Ukraine, August 31, 2015. Nearly 90 people were wounded and several of them were in a serious condition on Monday after several explosive devices were thrown from crowds in front of the Ukrainian parliament building in Kiev, the interior minister said in a Tweet. (Photo by Valentyn Ogirenko/Reuters)

A cloud of black smoke billows out the exhaust pipe of John Robertson's diesel dragster as he runs down the track during the 2015 NHRA Kansas Nationals, Friday, May 22, 2015, at Heartland Park in Topeka, Kan. (Photo by Chris Neal/The Topeka Capital-Journal via AP Photo)

A feminist activist uses a slingshot during a protest against gender violence and patriarchy in Santiago on November 29, 2019. Furious Chileans have since October 18 been protesting social and economic inequality, and against an entrenched political elite that comes from a small number of the wealthiest families in the country, among other issues. (Photo by Javier Torres/AFP Photo)