A German Shepard bares its teeth during Schutzhund attack dog training at Witmer-Tyson Imports February 14, 2002 in Newark, CA. (Photo by Justin Sullivan/Getty Images)

A candle burns during a vigil in Aotea Square to remember victims of the Paris attacks on November 14, 2015 in Auckland, New Zealand. According to reports, over 150 people were killed in a series of bombings and shootings across Paris, including at a soccer game at the Stade de France and a concert at the Bataclan theater. (Photo by Hannah Peters/Getty Images)

A man with blood on his shirt is evacuated from Brussels Airport in Zaventem, Belgium, on Tuesday, March 22, 2016. (Photo by Dirk Waem/Belga/Zuma Press/TNS)

A Kenyan soldier takes cover as shots are fired in front of Garissa University in Garissa town, located near the border with Somalia, some 370km northeast of the capital Nairobi, Kenya, 02 April 2015. At least 15 people have been killed and some 60 were injured in an attack carried out by Somalia's Islamist militant group al-Shabab, according to local media reports. (Photo by Dai Kurokawa/EPA)

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)

Afghan policemen take position at the site of a suicide attack followed by a clash between Afghan forces and insurgents after an attack on a Shi'ite Muslim mosque in Kabul, Afghanistan on Friday, August 25, 2017. Gunmen stormed a Shiite mosque in the Afghan capital while worshippers were at Friday prayers, setting off an explosion that killed a security guard outside and pushing into the shrine, officials said. (Photo by Omar Sobhani/Reuters)

Cats gather in front of a house damaged by shelling in the town of Dokuchayevsk, south of Donetsk, February 12, 2015. (Photo by Maxim Shemetov/Reuters)

First graders of a cadet's lyceum attend a ceremony to mark the start of the new school year in Kiev, Ukraine, September 1, 2015. September 1 marks the start of a new academic year for students in Ukraine.(Photo by Valentyn Ogirenko/Reuters)