At the end of World War II Hungary was liberated from the Nazis. It was occupied by the Soviet Union’s Red Army. Hungary's communists were led by General Secretary Mátyás Rákosi and backed by Joseph Stalin. The communists destroyed all political opposition. In 1949 Hungary officially became the People’s Republic of Hungary. Rákosi was an oppressive ruler. He exiled, imprisoned or killed over 300,000 Hungarians. After Stalin died, the soviet communists replaced Rákosi with Imre Nagy. They felt his softer approach would win them popularity. But the Kremlin decided he had become too popular. Rákosi was returned to power in April 1955. His secret police, the AVO, carried out Rákosi's oppressive orders again. The Hungarian people grew more and more tired of communist rule.