A serviceman walks near an APC while a helicopter flies on the position of the Ukrainian troops in Donetsk region on August 9, 2014. Fighting with pro-Russian separatists in eastern Ukraine has left 13 troops dead in the last 24 hours, Ukraine's military said Saturday. (Photo by Anatolii Stepanov/AFP Photo)

A Uyghur boy sits atop a horse as he has his picture taken outside the Id Kah Mosque before the Eid holiday on July 28, 2014 in old Kashgar, Xinjiang Province, China. Nearly 100 people have been killed in unrest in the restive Xinjiang Province in the last week in what authorities say is terrorism but advocacy groups claim is a result of a government crackdown to silence opposition to its policies. China's Muslim Uyghur ethnic group faces cultural and religious restrictions by the Chinese government. Beijing says it is investing heavily in the Xinjiang region but Uyghurs are increasingly dissatisfied with the influx of Han Chinese and uneven economic development. (Photo by Kevin Frayer/Getty Images)

A fisherman boats in Chao Lake where thick cyanobacteria gather on the surface on August 5, 2015 in Chaohu, Anhui Province of China. As high temperature came in summar, part of water in Anhui Province's Chao Lake breeds large tracts of cyanobacteria which not only brought pollution to sense of smell, but also affected people's life. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

A family wearing traditional Japanese clothing posed for a photograph during spring season in one of the garden in Kiyomizu dera, Kyoto prefecture, Japan on March 30, 2018. (Photo by Richard Atrero de Guzman/NurPhoto via Getty Images)

The front wheels of a tractor lift off the ground as the driver moves a heavy trailer outside Peshawar, Pakistan February 19, 2018. (Photo by Fayaz Aziz/Reuters)

This photo taken on April 7, 2018 shows Rohingya refugee attending a demonstration of elephant resistance arranged by the UNHCR and IUCN at the Kutupalong refugee camp in Ukhia, Bangladesh. The purpose of the training day is sobering – a dozen Rohingya have been killed by wild elephants whose habitat has been consumed by Kutupalong refugee camp. (Photo by Munir Uz Zaman/AFP Photo)

In a photo taken on June 5, 2017 a traffic security officer stands on duty at an intersection in Pyongyang. Officially known as traffic security officers but universally referred to as traffic ladies, they are chosen for their looks in a society that remains traditionalist in many respects. They must leave the role if they marry, and have a finite shelf-life, with compulsory retirement looming at just 26. (Photo by Ed Jones/AFP Photo)

Iraqi firefighters try to stop the fire of burning oil wells in Kirkuk, northern Iraq, 02 June 2016. Two Khabbaz oil field wells in Kirkuk Province, northern Iraq, exploded by suspected insurgents, a security official said. (Photo by EPA/Stringer)