Iron Curtain

Iron Curtain: The Crushing of Eastern Europe 1944-1956 by Anne Applebaum, Doubleday, 2012. 

Poland

In 1943, the Red Army created a Polish Infantry Division, named after Tadeusz Kościuszko, a famous Polish military engineer. Selected soldiers from this division and from Polish Communist parties were sent to NKVD training schools in Smolensk, Gorky and Kuibyshev.  As the Red Army pushed the Nazis back, these people became the security police in Poland.

Security Police

Installing Soviet-trained security police into Eastern European countries was one of the main ways the Soviet Union gained control of those countries.

Civic Organizations

Another method was to ban civic organizations. For example, Lásló Rank, Interior Minister of Hungary, banned the Roman Catholic youth group KALOT, which had been founded by Jesuits. He also banned the Hungarian Athletic Club, the Hungarian Naval Association and non-Communist trade unions.