Soviet occupation of the Baltic states ( 1940 ) The Soviet occupation of the Baltic states covers the period from the Soviet – Baltic mutual assistance pacts in 1939 , to their invasion and annexation in 1940 , to the mass deportation s of 1941 . In September and October 1939 the Soviet government compelled the much smaller Baltic states to conclude mutual assistance pacts which gave the Soviets the right to establish military base s there . Following invasion by the Red Army in the summer of 1940 , Soviet authorities compelled the Baltic governments to resign . The presidents of Estonia and Latvia were imprisoned and later died in Siberia . Under Soviet supervision , new governments of Communists and fellow traveler s arranged rigged election s with falsified results . Shortly thereafter , the Soviet - installed puppet governments requested admission into the Soviet Union . In June 1941 the new Soviet governments carried out mass deportations of " enemies of the people " . Consequently , at first many Balts greeted the Germans as liberators when they occupied the area a week later . Background . After the Soviet invasion of Poland on 17 September 1939 , the Soviets pressured Finland and the Baltic states to conclude mutual assistance treaties . The Soviets questioned the neutrality of Estonia following the escape of a Polish submarine from Tallinn on 18 September . A week after on 24 September , the Estonian foreign minister was given an ultimatum in Moscow . The Soviets demanded the conclusion of a treaty of mutual assistance to establish military bases in Estonia . The Estonians had no choice but to allow the establishment of Soviet naval , air and army bases on two Estonian islands and at the port of Paldiski . The corresponding agreement was signed on 28 September 1939 . Latvia followed on 5 October 1939 and Lithuania shortly thereafter , on 10 October 1939 . The agreements permitted the Soviet Union to establish military bases on the Baltic states ' territory for the duration of the European war and station 25 , 000 Soviet soldiers in Estonia , 30 , 000 in Latvia and 20 , 000 in Lithuania from October 1939 . New Soviet ultimatums . In 1939 Finland had rejected similar Soviet demands for military bases on Finnish territory . Consequently , the Soviet Union attacked Finland , starting the Winter War in November . The war ended in March 1940 with Finnish territorial losses exceeding the pre - war Soviet demands , but Finland kept its sovereignty . The Baltic states were neutral in the Winter War and the Soviets praised their relations with the USSR as exemplary . Soviet occupation . Soviet military plans . The Soviet troops allocated for possible military actions against the Baltic states numbered 435 , 000 troops , around 8 , 000 guns and mortars , over 3 , 000 tanks , and over 500 armoured cars . On June 3 , 1940 all Soviet military forces based in Baltic states were concentrated under the command of Aleksandr Loktionov . On June 9 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 . On June 12 , 1940 , according to the director of the Russian State Archive of the Naval Department Pavel Petrov ( C . Phil . ) referring to the records in the archive , the Soviet Baltic Fleet was ordered to implement a total military blockade of Estonia . On June 13 at 10 : 40 AM Soviet forces started to move to their positions and were ready by June 14 at 10 PM : Four submarines and a number of light navy units were positioned in the Baltic Sea , in the Gulfs of Riga and Finland to isolate the Baltic states by the sea ; a navy squadron including three destroyer divisions was positioned to the west of Naissaar in order to support the invasion ; the 1st marine brigade ' s four battalions were positioned on the transport ships " Sibir " , " 2nd Pjatiletka " and " Elton " for landings on the islands Naissaare and Aegna ; the transport ship " Dnester " and destroyers " Storozevoi " and " Silnoi " were positioned with troops for the invasion of the capital Tallinn ; the 50th battalion was positioned on ships for an invasion near Kunda . 120 Soviet vessels participated in the naval blockade , including one cruiser , seven destroyers , and seventeen submarines , along with 219 airplanes including the 8th air - brigade with 84 DB - 3 and Tupolev SB bomber s and the 10th brigade with 62 airplanes . On June 14 , 1940 , the Soviets issued an ultimatum to Lithuania . The Soviet military blockade of Estonia went into effect while the world ' s attention was focused on the fall of Paris to Nazi Germany . Two Soviet bombers downed the Finnish passenger airplane " Kaleva " flying from Tallinn to Helsinki carrying three diplomatic pouches from the U . S . legations in Tallinn , Riga and Helsinki . The US Foreign Service employee Henry W . Antheil , Jr . was killed in the crash . Red Army invades . On June 15 , the USSR invaded Lithuania and Soviet troops attacked the Latvia border guards at Masļenki . On June 16 , 1940 , the USSR invaded Estonia and Latvia . According to a " Time " magazine article published at the time of the invasions , in a matter of days around 500 , 000 Soviet Red Army troops occupied the three Baltic states — just one week before the Fall of France to Nazi Germany . Molotov accused the Baltic states of conspiracy against the Soviet Union and delivered an ultimatum to all Baltic countries for the establishment of Soviet - approved governments . 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 . Hundreds of thousands Soviet troops entered Estonia , Latvia , Lithuania . These additional Soviet military forces far outnumbered the armies of each country . 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 . The occupation of the Baltic states coincided with a communist coup d ' état in each country , supported by the Soviet troops . Most of the Estonian Defence Forces and the Estonian Defence League surrendered according to the orders of the Estonian Government and were disarmed by the Red Army . 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 , fighting the invading troops on 21 June 1940 . As the Red Army brought in additional reinforcements supported by six armoured fighting vehicle s , the battle lasted several hours until sundown . Finally the military resistance was ended with negotiation s and the Independent Signal Battalion surrendered and was disarmed . There were two dead Estonian servicemen , Aleksei Männikus and Johannes Mandre , and several wounded on the Estonian side and about ten killed and more wounded on the Soviet side . The Soviet militia that participated in the battle was led by Nikolai Stepulov . Winston Churchill , First Lord of the Admiralty at the time , said in his 1939 radio broadcast : That the Russian armies should stand on this line was clearly necessary for the safety of Russia against the Nazi menace . At any rate , the line is there , and an Eastern front has been created which Nazi Germany does not dare assail . When Herr von Ribbentrop was summoned to Moscow last week it was to learn the fact , and to accept the fact , that the Nazi designs upon the Baltic States and upon the Ukraine must come to a dead stop . Sovietization of the Baltic states . Political repressions followed with mass deportations carried out by the Soviets . The Serov Instructions , " " On the Procedure for carrying out the Deportation of Anti - Soviet Elements from Lithuania , Latvia , and Estonia " " , contained detailed procedures and protocols to observe in the deportation of Baltic nationals . The Soviets began a constitutional metamorphosis of the Baltic states by first forming transitional " People ' s Governments . " Led by Stalin ’ s close associates , and local communist supporters as well as official brought in from the Soviet Union , they forced the presidents and governments of all three countries to resign , replacing them with the provisional People ' s Governments . On July 14 – 15 , following illegal amendments to the electoral laws of the respective states , rigged parliamentary elections for the " People ' s Parliament s " were conducted by local Communists loyal to the Soviet Union . The laws were worded in such a way that the Communists and their allies were the only ones allowed to run . The election results were completely fabricated : the Soviet press service released them early , with the result that they had already appeared in print in a London newspaper a full 24 hours before the polls closed . The " People ' s Parliaments " met on July 21 , each with only one piece of business — a request to join the Soviet Union . These requests carried unanimously . In early August , the Supreme Soviet of the USSR " accepted " all three requests . The official Soviet line — a line carried on by Russia after the dissolution of the Soviet Union — is that all three Baltic states carried out socialist revolutions and voluntarily requested to join the Soviet Union . The new Soviet - installed governments in the Baltic states began to align their policies with current Soviet practices . According to the prevailing doctrine in the process , the old " bourgeois " societies were destroyed so that new socialist societies , run by loyal Soviet citizens , could be constructed in their place .