Estonia, Latvia and Lithunia were occupied by the Soviet Union for decades
Russia is examining the legality of the decision to recognise the independence of the Baltic republics in 1991 by the State Council of the USSR - according to Russia's state news service Interfax.
The decision to review recognition of the independence of EU-member Baltic nations follows the Russian Prosecutor General's Office ruling last year that Crimea was illegally handed to Ukraine in 1954; and is certain to alarm the small Baltic NATO-member nations of Lithuania, Latvia and Estonia.
In recent months Nato has held as series of meetings about how to address the threat from Russia and reassure Baltic countries that NATO is prepared to defend them. In June Poland and Lithuania confirmed that discussions were underway for the US to base heavy military weapons in warehouses across the Baltic states.
Speaking during a trip to Lithuania in June Europe NATO Supreme Allied Commander Europe General Phillip M. Breedlove said Russia's next steps were unpredictable and dangerous.
"We cannot fully be certain what Russia will do next, and we cannot fully grasp Putin's intent but what we can and are doing is learning from his actions. In addition what we see suggests growing Russian capabilities, significant military modernisation and ambitious strategic intent."
"In the east, Russia is blatantly attempting to change the rules and principles that have been the foundation of European security for decades. This challenge that's posed by resurgent Russia is global, not regional, and is enduring, not temporary."
The US has led a series of major NATO military drills in eastern Europe over the course of 2015 involving thousands of British, American and other allied forces.
Also in June Pentagon officials revealed a plan to base hundreds of battle tanks, high-caliber weapons and as many as 5,000 troops in the region - as a reposte to Russia's invasion of Ukraine and threat to NATO member states in eastern Europe.
The move would be the first time Washington has stationed heavy military equipment in the newer NATO member states that were once under Moscow's control.