The
Ministry for State Security (German:
Ministerium für Staatssicherheit, MfS), commonly known as the
Stasi (abbreviation , literally State Security), also State Security Service (German
Staatssicherheitsdienst, SSD), was the official state security service of the German Democratic Republic (GDR), or Deutsche Demokratische Republik (DDR), colloquially known as
East Germany. It has been described as one of the most effective and repressive
intelligence and
secret police agencies to have ever existed. The Stasi was headquartered in
East Berlin, with an extensive complex in
Berlin-Lichtenberg and several smaller facilities throughout the city. The Stasi motto was "
Schild und Schwert der Partei" (Shield and Sword of the Party), referring to the ruling
Socialist Unity Party of Germany (SED).