Kira Walkenhorst of Germany (L) signals as Doaa Elghobashy of Egypt (R) watches during the women's Beach Volleyball preliminary pool D game between Ludwig/Walkenhors of Germany and Elghobashy/Nada of Egypt the Rio 2016 Olympic Games at the Beach Volleyball Arena on Copacabana Beach in Rio de Janeiro, Brazil, 07 August 2016. (Photo by Antonio Lacerda/ANSA)

Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

Dancers audition for a post as cheerleaders of the Miami Dolphins, in Rio de Janeiro, Brazil, Thursday, March 3, 2016. Brazilian dancers audition in the first international cheerleader recruitment for the Miami Dolphins in Rio de Janeiro. The Dolphins will also hold auditions in Colombia, Argentina, Mexico and South of Florida. (Photo by Felipe Dana/AP Photo)

The hull on a boat that carried Rohingya migrants for three months is seen at Langkawi island, in the Malaysia's northern state of Kedah, Malaysia, May 12, 2015. Thailand and Malaysia may set up camps and detention centers to shelter hundreds of refugees arriving on their shores, officials said on Tuesday, as a leading inter-governmental agency said about 7,000 boat people were still adrift in the Bay of Bengal. (Photo by Olivia Harris/Reuters)

A tornado builds and travels southwest causing damage near Dean Rd. and 82nd Avenue in Hutchinson, Kan. on Monday, July 13, 2015. (Photo by Sandra J. Milburn/The Hutchinson News via AP Photo)

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.

Afghan children wait as their mothers receive treatment at a USAID-funded health center on September 7, 2011 in Farza, Afghanistan. Almost 10 years after the 9/11 attacks and the U.S. invasion of Afghanistan, the U.S. government funds some of 500 Afghan health facilities nationwide, most run by non-governmental organizations contracted by the Afghan Ministry of Public Health. (Photo by John Moore/Getty Images)

Andrea Rossato, Italy. Professional; Candid. Children enjoy the simple pleasures of a seaside holiday. (Photo by Andrea Rossato/Sony World Photography Awards)