From 1929 he was head of the Bulgarian sector of the Comintern in Berlin. When the Reichstag was burned (1933) he was accused with other communists of complicity. His powerful defence at his trial forced the Nazis to release him and he settled in Moscow. In 1945 he was appointed head of the communist government in Bulgaria, which led to the setting up of the Bulgarian People’s Republic (1946) under his premiership, a period marked by ruthless Sovietization.