Under Soviet supervision, new puppet communist governments and fellow travelers arranged rigged elections with falsified results.

[2] Shortly thereafter, the newly elected "people's assemblies" passed resolutions requesting admission into the Soviet Union.

The Soviets demanded that Finland cede or lease parts of its territory, as well as the destruction of Finnish defenses along the Karelian Isthmus.

[9][10] The initial period of the war proved disastrous for the Soviet military, taking severe losses while making little headway.

[16] On 9 June the directive 02622ss/ov was given to the Red Army's Leningrad Military District by Semyon Timoshenko to be ready by 12 June to a) capture the vessels of the Estonian, Latvian and Lithuanian navies in their bases or at sea; b) capture the Estonian and Latvian commercial fleets 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 the 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; and g) prevent Estonian and Latvian airplanes from flying either to Finland or Sweden.

referring to the records in the archive,[18][19] the Soviet Baltic Fleet was ordered to implement a total military blockade of Estonia.

The Soviet military blockade of Estonia went into effect while the world's attention was focused on the fall of Paris to Nazi Germany.

On 18 June 1940 the German Ambassador to the Soviet Union Graf von der Schulenburg in his telegram have said that earlier V. Molotov had "warmly" congratulated him on Germany's recent success in France and added that:[a] «[…] it had become necessary to put an end to all the intrigues by which England and France had tried to sow discord and mistrust between Germany and the Soviet Union in the Baltic States.

Threatening invasion and accusing the three states of violating the original pacts as well as forming a conspiracy against the Soviet Union, Moscow presented ultimatums, demanding new concessions, which included the replacement of their governments and allowing an unlimited number of troops to enter the three countries.

[27][28][29][30] The Baltic governments had decided that, given their international isolation and the overwhelming Soviet forces on their borders and already on their territories, it was futile to actively resist and better to avoid bloodshed in an unwinnable war.

[33] The Soviet troops attacked the Latvian border guards at Masļenki[34] before invading Latvia and Estonia on 16 June.

[37][38] Only the Estonian Independent Signal Battalion stationed in Tallinn at Raua Street showed resistance to the Red Army and "People's Self-Defence" Communist militia,[39] fighting the invading troops on 21 June 1940.

[40] As the Red Army brought in additional reinforcements supported by six armoured fighting vehicles, the battle lasted several hours until sundown.

Latvia and Lithuania managed to preserve exile diplomatic services that had received emergency powers to represent the countries abroad, that worked as de facto governments-in-exile.

On 14–15 July, following illegal amendments to the electoral laws of the respective states, rigged parliamentary elections for the "People's Parliaments"[48] were conducted by local Communists loyal to the Soviet Union.