Firefighting teams try to extinguish an oil fire November 27, 2016 as smoke billows from one of the remaining oil wells set ablaze by ISIL in their retreat from Qayyarah at the start of the Mosul offensive which began more than a month prior. (Photo by Byron Smith/ZUMA Wire/Rex Features/Shutterstock)

A Iraqi soldier of the 9th division is seen within a Humvee in Shyma district in Mosul, Iraq, Tuesday, December 6, 2016. Iraqi forces, backed by the U.S.-led international coalition, launched a campaign in October to retake Mosul, the country's second largest city and IS's last major urban bastion in Iraq. (Photo by Manu Brabo/AP Photo)

Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

A man and a woman both wounded by what locals say was recent shelling by Ukrainian forces, react as they sit in an ambulance in Donetsk August 23, 2014. (Photo by Maxim Shemetov/Reuters)

A marine aims an RPG-7, a portable rocket- propelled grenade launcher, during military exercises conducted by the Russian Pacific Fleet' s naval infantry unit at the Bamburovo firing range on February 2, 2017. The drills are a part of preparations for the Suvorov Attack and Sniper Line army competitions. (Photo by Yuri Smityuk/TASS)

An Iraqi Kurdish Peshmerga takes part in a graduation ceremony at the Zakho military academy in the Iraqi Kurdish town of Zakho, some 500 kilometres north of Baghdad, on January 30, 2018. (Photo by Safin Hamed/AFP Photo)

A girl holds her brother in her arm as black smoke rises after an oil well set on fire in the center of al-Kayyara town to the south of Daesh terror organization-held Mosul in Iraq on October 25, 2016. The oil well in the center of al-Kayyara town, which was set alight by retreating Daesh militants in advance of the Iraqi army's takeover of the town on August 24, 2016 has still not entirely been put out. The raw petrol which is still alight is creating black clouds above the city. The residents and wildlife beneath this polluting smoke cloud may find their health at risk. The effects of the fire in the town center on unprotected civilians' health can easily be seen on the hands and faces of children playing on the street. (Photo by dris Okuducu/Anadolu Agency/Getty Images)

Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)