Martin Lacey Jr. with a lion during the premiere of the Circus Krone program “Circus der Preistraeger” at Circus Krone on February 2, 2016 in Munich, Germany. (Photo by Hannes Magerstaedt/Getty Images)

A burning train wagon is seen after an explosion at Lac Megantic, Quebec, July 6, 2013. A large swath of Lac Megantic was destroyed Saturday after a train carrying crude oil derailed, sparking several explosions and forcing the evacuation of up to 1,000 people. (Photo by Mathieu Belanger/Reuters)

A spiritual leader (R) of the Huni Kui Indian tribe blows an herbal powder into the nose of a tribal member during a ceremony outside the village of Novo Segredo along the Envira river of Brazil's northwestern Acre state, March 9, 2014. Many indigenous groups, including the Huni Kui, Ashaninka, and Madija, live in villages in the Brazilian rainforest near the border with Peru. (Photo by Lunae Parracho/Reuters)

A girl jumps to touch cherry blossoms in full bloom in Fussa, outskirts Tokyo, Japan, 05 April 2014. Temperatures being very constant made blossoms to keep full bloom for holiday makers. (Photo by Kimimasa Mayama/EPA)

Throughout the course of the long war in Afghanistan, Coalition troops have relied on thousands of military working dogs to help keep them safe, and make their jobs easier. The dogs are trained to detect explosives, to find illegal drugs, to search for missing comrades, or target enemy combatants. Not only are they active on the front lines, but behind the lines they serve as therapy dogs, service dogs, and loyal companions. They also share the same risks as the ground troops, suffering injuries and sometimes death on the battlefields. Gathered here are images of these dogs and their handlers in Afghanistan and back home, from over the past several years, part of the ongoing series here on Afghanistan.

A boy uses a mobile phone as he sits inside his father's snacks shop along a road in Kolkata, India, February 22, 2016. (Photo by Rupak De Chowdhuri/Reuters)

Boys play with a drainage culvert used for flood control in Las Pinas, Metro Manila February 28, 2016. (Photo by Erik De Castro/Reuters)

A woman photographs a Norwegian spruce Christmas tree from Oslo after it was lit at Trafalgar Square in central London, December 4, 2014. (Photo by Toby Melville/Reuters)