Simon Sebag Montefiore estimated that 15 million kulaks and their families were deported by 1937, during the deportation many people died, but the full number is not known. Retreat by Soviet forces in 1941 Deportations, summary executions of political prisoners and the burning of foodstocks and villages took place when the Red Army retreated before the advancing Axis forces in 1941. In the Baltic States, Belarus, Ukraine, and Bessarabia, the NKVD and attached units of the Red Army massacred prisoners and political opponents before fleeing from the advancing Axis forces. Deportation of Greeks The prosecution of Greeks in the USSR was gradual: at first the authorities shut down the Greek schools, cultural centres, and publishing houses. Then, in 1942, 1944 and 1949, the NKVD indiscriminately arrested all Greek men 16 years old or older. All Greeks who were wealthy or self-employed professionals were sought for prosecution first. This affected mostly Pontic Greeks and other Minorities in the Krasnodar Krai and along the Black Sea coast. By one estimate, around 50,000 Greeks were deported. On 25 September 1956, MVD Order N 0402 was adopted and defined the removal of restrictions towards the deported peoples in the special settlements. Afterward, the Soviet Greeks started returning to their homes, or emigrating towards Greece. Deportation of Kalmyks During the Kalmyk deportations of 1943, codenamed Operation Ulussy (Операция "Улусы"), the deportation of most people of the Kalmyk nationality in the Soviet Union (USSR), and Russian women married to Kalmyks, but excluding Kalmyk women married to men of other nationalities, around half of all (97-98,000) Kalmyk people deported to Siberia died before being allowed to return home in 1957. Deportation of Crimean Tatars After the retreat of the Wehrmacht from Crimea, the NKVD deported around 200,000 Crimean Tatars from the peninsula on 18 May 1944. Deportation of Ingrian Finns By 1939 the Ingrian Finnish population had decreased to about 50,000, which was about 43% of 1928 population figures, and the Ingrian Finn national district was abolished., Following the German invasion of the Soviet Union and the beginning of the Leningrad Blockade, in early 1942 all 20,000 Ingrian Finns remaining in Soviet-controlled territory were deported to Siberia. Most of the Ingrian Finns together with Votes and Izhorians living in German-occupied territory were evacuated to Finland in 1943–1944. After Finland sued for peace, it was forced to return the evacuees. Soviet authorities did not allow the 55,733 people