The NKVD undertook mass extrajudicial executions of untold numbers of citizens, and conceived, populated and administered the Gulag system of forced labour camps. Their agents were responsible for the repression of the wealthier peasantry, as well as the mass deportations of entire nationalities to uninhabited regions of the country. They oversaw the protection of Soviet borders and espionage (which included political assassinations), and enforced Soviet policy in communist movements and puppet governments in other countries, most notably the repression and massacres in Poland.