The mass internment of civilians by military or police forces for indefinite periods of time and under inhumane conditions characterizes concentration camps and gulags. Many prisoners serve out their sentences in reform through labour camps, whose function is not fully explained in the legal code. Prisoners may even be forbidden to return home after they are released and must remain in the area, thus amounting to a form of internal exile.
Political prisoners are detained en masse in South Africa, Cuba and the USSR. Refugee camp conditions, as in Lebanon, assume the features of mass detention. In China in 1989 it was estimated that some of the labour camps held up to 40,000 inmates together with their families, juvenile offenders and some freed workers who were confined to the region.
There were about 220 labour camps established in the Czech lands during World War II. Many of them were overcrowded, such as the Lety camp, designed to hold 300 people in the summer and 200 in the winter, that held 900 men, women and children at peak times. The guards were under signed orders to shoot anyone attempting to escape or disobeying an order. The inmates, including children, were forced to work from dawn to dusk in stone quarries, on road construction and cutting wood.