In September 1941 , the Soviet Union joined the Atlantic Charter which affirmed , among other things , the " desire to see no territorial changes that do not accord with the freely expressed wishes of the peoples concerned " and to " respect the rights of all peoples to choose the form of government under which they will live ; and they wish to see sovereign rights and self-government restored to those who have been forcibly deprived of them . ... " The Soviet Union reoccupied the Baltic states as part of the Baltic Offensive in 1944 . In 1945 , the Soviet Union signed the Yalta Declaration declaring for the reestablishment of order in Europe according to the principle of the Atlantic Charter " the right of all peoples to choose the form of government under which they will live , the restoration of sovereign rights and self-government to those peoples who have been forcibly deprived of them by the aggressor nations . " The Yalta declaration further states that " to foster the conditions in which the liberated peoples may exercise these rights , the three governments will join ... among others to facilitate where necessary the holding of free elections . " After the Soviet re-invasion , the Baltic countries remained the Soviet Socialist Republics of the Estonian Soviet Socialist Republic , the Latvian Soviet Socialist Republic and the Lithuanian Soviet Socialist Republic . On 12 January 1949 the Soviet Council of Ministers issued a decree " on the expulsion and deportation " from Baltic states of " all kulaks and their families , the families of bandits and nationalists " , and others . Ten percent of the entire adult Baltic population was deported or sent to labor camps . After World War II , as part of the goal to more fully integrate Baltic countries into the Soviet Union , mass deportations were concluded in the Baltic countries and the policy of encouraging Soviet immigration to the Baltic states continued
Yalta Declaration
Yalta Conference
Baltic–Soviet relations