The Territorial Defense Forces (Polish: Obrona Terytorium Kraju - OTK) was an armed force responsible for the internal security of Poland and separate from the Polish Army. The OTK existed from 1965 until 2008. As initially organized, OTK forces included both an "Internal Defense Army" and the "Border Defense Force". This style of internal security organization corresponded to that used by the Soviet Union during the same period. After the fall of communism in Poland, changed political priorities led to the reduction of OTK forces. By 1 July 2008, the last of its battalions were converted to mechanized units of the army.