The deportation took place from May 22 to June 20, 1941, just before the invasion of the Soviet Union by Nazi Germany. However, the goal of the deportations was to remove political opponents of the Soviet government, not to strengthen security in preparation for the German attack.
The deportation took place a year after the occupation and annexation of the Baltic states and Bessarabia and Northern Bukovina and targeted "anti-Soviet elements" – former politicians, policemen, wealthy industrialists and landowners, etc. In occupied Poland, it was the fourth wave of mass deportations and was intended to combat the "counter-revolutionary" Organization of Ukrainian Nationalists.
The procedure for the deportations was approved by Ivan Serov in the so-called Serov Instructions. People were deported without trials in whole families. Men were generally imprisoned and most of them died in Siberian prison camps (see Gulag); women and children were resettled in forced settlements in Omsk and Novosibirsk Oblasts, Krasnoyarsk and Altai Krais, and Kazakhstan. The mortality rate among the Estonian deportees was estimated at 60%.