An Afghan policeman stands guard as smoke and flames rise from the site of a huge blast struck near the entrance of Kabul's international airport, in Kabul on August 10, 2015. A huge blast struck near the entrance of Kabul's international airport on August 10 during the peak lunchtime period, officials said, warning that heavy casualties were expected. “The explosion occurred at the first check point of Kabul airport”, said deputy Kabul police chief Sayed Gul Agha Rouhani. (Photo by Shah Marai/AFP Photo)

Iraqi Kurdish female fighter Haseba Nauzad looks through a pair of binoculars during a deployment near the frontline of the fight against Islamic State militants in Nawaran near Mosul, Iraq, April 20, 2016. (Photo by Ahmed Jadallah/Reuters)

Iranian-Kurdish female fighters hold their weapons during a battle with Islamic State militants in Bashiqa, near Mosul, Iraq on November 3, 2016. (Photo by Ahmed Jadallah/Reuters)

An Afghan policeman carries a wounded man at the site of a suicide attack in Kabul March 25, 2015. Six people were killed and more than 30 injured in the suicide bombing in the Afghan capital on Wednesday that struck close to the presidential palace in the heart of the city, the Interior Ministry said. The suicide bomber had been travelling in a vehicle packed with explosives and it was not immediately clear what the target of the attack had been. (Photo by Omar Sobhani/Reuters)

Military vehicles surround a wreckage of a trolleybus, in Volgograd, Russia, Monday, December 30, 2013. A bomb blast tore through a trolleybus in the city of Volgograd on Monday morning, killing at least 10 people a day after a suicide bombing that killed at least 17 at the city's main railway station. Volgograd is about 650 kilometers (400 miles) northeast of Sochi, where the Olympics are to be held. (Photo by Denis Tyrin/AP Photo)

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)

Sydney artist Phillip George poses with two surfboards of his own design at Marks Park, Tamarama on December 16, 2008 in Sydney, Australia. (Photo by Don Arnold/Getty Images)

Lindsay Knutson plays in the heavy snow with her family dog, Aspen, and daughter Flora Bejblik, 4, cq, as her husband Bob Bejblik, rear left, shovels, Tuesday, March 5, 2013 in southwest Minneapolis. The National Weather Service predicted a two-day snow total of 8 to 12 inches for much of southeastern and east-central Minnesota, including the Twin Cities. (Photo by Elizabeth Flores/AP Photo/The Star Tribune)