After the war, Estonia remained incorporated into the Soviet Union as the Estonian SSR until 1991, although the Atlantic Charter stated that no territorial arrangements shall be made.
World War II losses in Estonia, estimated at around 25% of the population, were among the highest proportion in Europe.
Finland held out in the Winter War until March 1940, when the Moscow Peace Treaty was signed.
5 divisions of the Soviet Air Force with 1150 aircraft blockaded the whole Baltic air space against Estonia, Lithuania and Latvia.
The Soviet Baltic Fleet blockaded the operation from the sea.
Men who avoided these mobilisations, fled to Finland to be formed into the Finnish Infantry Regiment 200.
About 40% of the Estonian pre-war fleet was requisitioned by British authorities and used in Atlantic convoys.
Estonia passed a law ratifying its neutrality on December 1st, 1938, which was modelled on Sweden's declaration of neutrality of May 29, 1938.
Early in the morning of August 24, 1939, the Soviet Union and Nazi Germany signed a 10-year non-aggression pact, called the Molotov–Ribbentrop pact.In the summer of 1940 the occupation of Estonia was carried through as a regular military operation.160,000 men, supported by 600 tanks were concentrated for the invasion into Estonia.The Soviet NKVD was ordered to be ready for the reception of 58,000 prisoners of war.On June 9, the directive 02622ss/ov was given to the Red Army's Leningrad Military District by Semyon Timoshenko to be ready by June 12 to (a) Capture the vessels of the Estonian, Latvian and Lithuanian Navy in their bases and/or at sea; (b) Capture the Estonian and Latvian commercial fleet and all other vessels; (c) Prepare for an invasion and landing in Tallinn and Paldiski; (d) Close the Gulf of Riga and blockade the coasts of Estonia and Latvia in Gulf of Finland and Baltic Sea; (e) Prevent an evacuation of the Estonian and Latvian governments, military forces and assets; (f) Provide naval support for an invasion towards Rakvere; (g) Prevent Estonian and Latvian airplanes from flying either to Finland or Sweden.Estonia was occupied by Germany and incorporated into Reichskommissariat Ostland.