Melissa Stewart's team competes in the official restart of the Iditarod, a nearly 1,000 mile (1,610 km) sled dog race across the Alaskan wilderness, in Fairbanks, Alaska, U.S. March 6, 2017. (Photo by Nathaniel Wilder/Reuters)

A Husky dog looks on before a sled and skijoring race in the village of Kadnikovo outside Yekaterinburg, Russia, December 10, 2016. (Photo by Maxim Shemetov/Reuters)

A dog in a purple dress, taken in El Dorado, Arkansas, December 2016. The dapper dogs in clothes are back with a second series, and they’re feeling festive. (Photo by Tammy Swarek/Barcroft Images)

A photographer has created a series of paw-traits of hungry dogs pulling hilarious faces as they try and catch treats. Using a unique technique, the shots are captured at the exact moment the adorable pooches attempt to catch an airborne piece of food. The dogs appear surprised, happy, sad, confused – and sometimes even so blasé they miss the treat entirely. The images were taken by Christian Vieler, a photographer from Waltrop, Germany. Here: A labrador retriever. (Photo by Christian Vieler/Caters News)

A man cuts dog meat at a dog meat restaurant ahead of local dog meat festival in Yulin, Guangxi Zhuang Autonomous Region, China on June 21, 2018. The festival in the southwestern town of Yulin has long drawn international criticism, with thousands of dogs traditionally being killed during the event. (Photo by Tyrone Siu/Reuters)

A Palestinian female volunteers for the al- Aqsa Martyrs Brigade, a militant group part of Fatah movement, stands with her weapon in this undated photo. Unlike Hamas and Islamic Jihad, the ideology of al-Aqsa is rooted in Palestinian nationalism not political Islam, and is the only Palestinian group that accepts and trains women to be “martyrs”. (Photograph by Courtney Kealy/Getty Images)

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.