Concentration camp
These camps are called zone in Russian.  They are also commonly called "gulags". GULAG is an acronym for the Russian words "Main Camp Administration" (ru: Главное управление лагерей и мест заключения; Glavnoe upravlenye lagerey i mest zaklyucheniya).  This was the government agency that was in charge of the prison camps while Josef Stalin led the Soviet Union.  However, people who do not speak Russian often use the word "gulag" to talk about any forced labor camp in Russia or the Soviet Union.