Two types of compulsory labor forces emerged after the communist seizure of power in 1944. The Labor Army continued in existence and, following the example of the Soviet Union under Stalin and of the other states in the Soviet post-World War II orbit, Bulgaria also placed those of its citizens considered politically dangerous in forced labor camps. These were the prison colonies populated by victims of the secret police, persons who might or might not have had proper trials but who were considered to be enemies of the party or the government. Some camps were temporarily located at sites where large numbers of manual laborers were needed, but more often camps were at permanent locations. Buildings at all camps were flimsy, and facilities were minimal. In the early period, while the Communists were establishing their control over the country, about 1 percent of the population was imprisoned at hard labor in such camps at any given time. In the early 1970s the Construction Troops organization that had evolved from the Labor Army was military in form and character. Its men were provided from the annual draft and were subject to military regulations and discipline. Its officers, who had regular military ranks, were provided from the armed forces or had been prepared for that specific assignment in the Construction Troops own school. The headquarters of the organization, however, was a main administration responsible directly to the Council of Ministers; it was not within either the Ministry of National Defense or the Ministry of Internal Affairs. Furthermore, the work of the organization was heavy construction and, at least in peacetime, the greatest portion of it was unrelated to any requirement of the armed forces. The Construction Troops worked on various construction projects on a five-day-week basis but assumed a military routine on Saturdays, which were devoted to platoon and company drill and to political education classes. Until the mid-1960s the troops were used mainly in roadbuilding and land reclamation. By the early 1970s more than one-half of their work was in factory, housing, water supply, and other such construction. Its 1972 projects included building a tire manufacturing plant and a resort hotel complex and harnessing a river for hydroelectric power, recreation, and supplies of irrigation water and city water. One of the organization's spokesmen claimed that there was not a large-scale project underway anywhere in the country where its troops were not at work. The men acquired in the annual draft serve two years, which satisfies their military service obligation. Almost all of the conscripts in the Construction Troops work as unskilled laborers. During or at the end of their two-year tours, those who enjoy or show a special aptitude for construction work may volunteer for extended duty tours and serve as noncommissioned officers. Some of those who are accepted are sent to technical schools for further education.