The complex relationship between the Soviet Union and Vietnam had its origins in the Communist International (Comintern), an organization founded in Moscow in 1919.
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The Comintern lent its support to countries struggling to extricate themselves from Western colonial rule. Between 1930 and 1950, the Soviet Union assumed a brotherly role towards Vietnam, providing military training and political advice to Vietnamese revolutionaries.
In 1945, Ho Chi Minh proclaimed the formation of the Democratic Republic of Vietnam (DRV), independent from French colonial rule.
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1954 saw France relinquish its claim to former colonies and Vietnam was then divided into the DRV (North) and noncommunist Republic of Vietnam (South). In the late 1950s, when Vietnamese communists rebelled against the American-backed South Vietnam, the USSR’s support of the DRV intensified.
Following the Americans’ exit in 1975, the USSR extended its air and naval forces into Vietnam. In November 1978, the Soviet Union and the Socialist Republic of Vietnam (as the DRV was now known) signed a Treaty of Friendship.
The USSR also supported Vietnam’s invasion and occupation of Cambodia despite widespread condemnation from other nations.