The KGB was a security agency .
ogg , p = kəmjɪˈtjet ɡəsʊˈdarstvjɪnːəj bjɪzɐˈpasnəsjtjɪ -RSB- , translated in English as Committee for State Security -RRB- , was the main security agency for the Soviet Union from 1954 until its break-up in 1991 .