The SVR has declassified documents relating to the situation in the three Baltic countries in early 1940s and during World War II, said the chief spokesman of the intelligence service, Sergei Ivanov.
"These materials show that German-oriented policies conducted by governments in Latvia, Lithuania and Estonia threatened to turn these states into a staging ground for a German invasion of the Soviet Union," Ivanov said.
The issue of the Soviet Union's annexation of the Baltic states continues to be a source of contention between Russia and its EU Baltic neighbors, particularly Latvia and Estonia, which have denied citizenship to thousands of their ethnic Russian residents, over what they call the illegal Soviet "occupation".
Ivanov said, "The archives contain special reports to the [Soviet] political leadership on secret talks between Latvian leaders and the Germans, about the inevitability of a future occupation of Estonia by German troops, and the readiness of the Lithuanian army to surrender to the Germans."
He also said declassified documents indicate that the United States and Great Britain accepted the entry of Soviet troops into the three Baltic states in 1940 as a necessary and timely step.
In June 1940, Russia accused Estonia of forming a conspiracy together with Latvia and Lithuania against it, and issued an ultimatum, demanding among other concessions that more Soviet troops be allowed to enter the three countries.
In the following month, local communists loyal to the Soviet Union won parliamentary "elections" in all three countries, and in August these parliaments asked the Soviet government for accession to the Soviet Union. As a result, the three states were formally annexed.
"The declassified SVR archives serve as a comprehensive addition to historical knowledge about the situation in the Baltic region during the Second World War and its role as a crossroads of geopolitical interests and confrontation between the Axis and Allies," the SRV official said.