Arbeitskommandos, officially called Kriegsgefangenenarbeitskommando, were sub-camps under prisoner-of-war camps for holding prisoners of war of lower ranks (below sergeant), who were working in industries and on farms. 

These camps were permitted under the Third Geneva Convention provided prisoners were accorded proper treatment. They were not allowed to work in industries manufacturing war materials, but this restriction was frequently ignored by the Germans. They were always under the administration of the parent prisoner-of-war camp, which maintained records, distributed International Red Cross packages, and provided at least minimal medical care in the event of the prisoner's sickness or injury. The number of prisoners in an Arbeitskommando was usually between 100 and 300.

These were different from subcamps of Nazi concentration camps operated by the SS, which were also called Arbeitskommando. Because of the two different types, there is some confusion in the literature, with the result of occasional reports of prisoners-of-war being held in concentration camps. In some cases, the two types were physically adjacent, when both POWs and KL-inmates were working at large facilities such as coal mines or chemical plants. They were always kept apart from each other.

[http://en.wikipedia.org/wiki/Arbeitslager#Arbeitskommandos]