An Egyptian army soldier stands guard near debris from a Russian airliner which crashed at the Hassana area in Arish city, north Egypt, November 1, 2015. Russia has grounded Airbus A321 jets flown by the Kogalymavia airline, Interfax news agency reported on Sunday, after one of its fleet crashed in Egypt's Sinai Peninsula, killing all 224 people on board. (Photo by Mohamed Abd El Ghany/Reuters)

An Afghan man is carried out of a hospital after receiving treatment following a suicide truck bomb attack in Kabul, Afghanistan August 7, 2015. The bombings were the first in Kabul since Mullah Akhtar Mansour took charge of the Taliban last week, and followed a rare truck bomb attack in an eastern province on Thursday. (Photo by Omar Sobhani/Reuters)

A Syrian boy is comforted as he cries next to the body of a relative who died in a reported airstrike on April 27, 2016 in the rebel-held neighbourhood of al-Soukour in the northern city of Aleppo. The Syrian army was preparing an offensive to retake the whole of Aleppo, as fighting in the divided second city killed 38 civilians in a new blow for a tattered truce. Nearly 200 people have been killed in Aleppo in the past week as rebels have pounded government-held neighbourhoods with rocket and artillery fire and the regime has hit rebel areas with air raids. (Photo by Karam Al-Masri/AFP Photo)

Workers lay railway track in a tunnel of the Crossrail project in Stepney, east London, Britain, November 16, 2016. Crossrail, which is Europe's largest construction project, is a railway link which will connect outlying areas to the east and west of London with tunnels under the centre of the capital. (Photo by Stefan Wermuth/Reuters)

An armed man herds his cattle close to the village of Nimini in northern South Sudan, February 8, 2017. In the chaos of South Sudan's civil war, it took three years for Nyagonga Machul to find her lost children. Machul had traveled from her village to the capital when President Salva Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer, in 2013. (Photo by Siegfried Modola/Reuters)

A “nail house”, the last building in the area, sits in the middle of a road under construction in Nanning, Guangxi Zhuang Autonomous Region April 10, 2015. According to local media, the owner of the house didn't reach an agreement with the local authority about compensation of the demolition. (Photo by Reuters/Stringer)

A man checks his mobile phone near overturned shipping containers after explosions hit the Binhai new district, Tianjin, August 13, 2015. A huge explosion hit an industrial area in the northeastern Chinese city of Tianjin late on Wednesday evening, triggering a blast wave felt several kilometres away and injuring at least 50 people, domestic media reported. (Photo by Reuters/Stringer)

A building burns after an explosion on 2nd Avenue on March 26, 2015 in New York City. The seven alarm fire drew firefighters from across the city. A number of injuries have been reported. (Photo by Andrew Burton/Getty Images)