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.

In this March 13, 2015 photo, Yohan, 4, from left, Cristian, 7, and Angelo, 6, playfully toss coca leaves into the air, singing: “I have a lot of money, look at all the money I have”, in La Mar, province of Ayacucho, Peru. Hauling cocaine out of the remote valley is about the only way to earn decent cash in this region where a farmhand earns less than $10 a day. Beyond extinguishing young lives, the practice has packed Peru's highland prisons with cocaine backpackers while their bosses evade incarceration. (Photo by Rodrigo Abd/AP Photo)

A Colombian air force helicopter retrieves the bodies of victims from the wreckage of a plane that crashed into the Colombian jungle with Brazilian soccer team Chapecoense onboard near Medellin, Colombia, November 29, 2016. The chartered plane was carrying a Brazilian soccer team to the biggest match of its history when it crashed into a Colombian hillside and broke into pieces, killing 75 people and leaving six survivors, Colombian officials said Tuesday. (Photo by Jaime Saldarriaga/Reuters)

Women take a selfie next to a police officer as they take part in New Year's Eve celebrations in the Bund, in Shanghai, China December 31, 2016. (Photo by Aly Song/Reuters)

Abbey Clancy attends Warner Music Brits after party on February 22, 2017 in London, England. (Photo by FameFlynet)

Italian actress Sophia Loren and US actor Marlon Brando at a cinema in Rome on November 11, 1954, where Brando received the Francesco Pasinetti Prize for his performance in the film “On The Waterfront”. (Photo by Keystone/Getty Images)

Female police officers from Istanbul's Motorcycled Police Unit wait to search vehicles during a roadside checkpoint operation on March 7, 2017 in Istanbul, Turkey. The rapid response unit nicknamed Dolphins is used primarily in crime prevention operations and has 25 female officers. 6% of Turkey's 250,000 strong police force are women, March 8 marks International Women's Day. (Photo by Chris McGrath/Getty Images)

Girls sit inside an empty classroom as they pose for a photograph during a celebration marking the end of the school year in the town of Douma, eastern Ghouta in Damascus, Syria May 21, 2016. (Photo by Bassam Khabieh/Reuters)