A local resident of Red Hook, Betty Walsh, crosses a flooded street in Red Hook August 28, 2011 in the Brooklyn borough of New York City. While Hurricane Irene has been downgraded to a tropical storm, it has knocked out power to more than 3 million people and is attributed to 15 deaths as it travels up the Eastern seaboard. (Photo by Robert Nickelsberg/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.

World War II veteran Jack W. Schlegel, 91 years-old, from Mount Tremper, New York, of the 508th Parachute Infantry Division of the 82nd Airborne who parachuted near Sainte-Mere-Eglise on June 6,1944, poses with American and French flags as he visits the American War cemetery in Colleville-sur-Mer, on the Normandy coast June 2, 2014. REUTERS/Pascal Rossignol

Cocoa Beach, Florida, USA. 7th October, 2016. Kaleigh Black, 14, left, and Amber Olsen, 12, run for cover as a squall with rain and wind pelt them while they explore the Cocoa Beach Pier on Friday (10/7/16) after hurricane Matthew passed to the east on Florida's east coast.(Photo by Douglas R. Clifford/Tampa Bay Times/ZUMA Wire/Alamy Live News)

People sit on the top of a truck heavily piled with corn-stalks plies as they head for Mogadishu from Afgooye on October 19, 2016. At least four police officers were killed on October 18 when a suicide bomb attacker rammed an explosives-packed car into a police station before fighters from the Al-Qaeda-linked Shabaab group subsequently stormed the area killing at least 10 people, including soldiers and civilians. (Photo by Mohamed Abdiwahab/AFP Photo)

A plastinated body presented as a pole vaulter is exhibited at the Menschen Museum, Museum of Humans, in Berlin, August 29, 2016. The museum was caught up in a legal dispute with the district office of Berlin-Mitte for years before it was able to meet the requirements made by the court. (Photo by Sophia Kembowski/DPA Photo via Newscom)

A sеxy model poses for photos during the 2016 Guangzhou Sеx Culture Festival in Guangzhou city, south China' s Guangdong province on November 10, 2016. The festival has featured the latest developments and technologies of Adult toys and reproductive health products in the country. (Photo by Asia Wire)

A young anoa, also known as midget buffalo, named Tycoon runs around at the Zoo in Berlin, Germany, on November 9, 2012. (Photo by Maurizio Gambarini/EPA)