Estonia plans to press Russia for compensation for damage it says was caused during decades of Soviet rule.
Many thousands of Estonians perished in Stalin's labour camps
The process began as the Baltic state's special commission presented parliament with the so-called "White Book" detailing the damage.
The document says Estonia lost 180,000 people during the Soviet occupation in 1940-41 and then again in 1944-91 after four years of Nazi rule.
It says the presence of the Soviet army alone cost Estonia $4bn.
However, Estonian lawmakers - who were given the document earlier this week - admit that the process is likely to be lengthy and will anger Russia, the main successor to the Soviet Union.
Leonid Slutsky, deputy head of Russian parliament's committee on external affairs, has already told Moscow's Echo Moskvy radio that Estonia's plans amount to "anti-Russian gibberish".
'Another 10 years'
A draft resolution by Estonia's parliament urged the government to submit a report by 1 January 2005, detailing the feasibility of any legal action against Moscow.
ESTONIA'S FOREIGN MASTERS
Russia takes control of Estonia in the 1700s from Sweden
Germany invades in 1918; takes formal control in peace treaty with Russia's new Soviet rulers
Estonia declares independence in 1918
Soviet troops invade Estonia in 1940 allowed in Hitler-Stalin pact
60,000 Estonians die or are deported in first month of occupation
Hitler invades in 1941, backed by Estonian fighters
The Red Army returns in 1944, remains until early 1990s
"We would first like to see that the government makes a realistic prognosis based on international laws," parliamentary constitutional commission chairman Urmas Reinsalu told BBC News Online.
Mr Reinsalu also said lawmakers wanted to have further debates on the findings of the book, which took the special commission investigating the Nazi and Soviet occupation 12 years to compile.
Earlier, the head of the commission, Vello Sallo, told Russia's Interfax news agency that "scientists will have to work for at least another 10 years" to get more detailed data.
Mr Salo also explained that the document "mostly centred on the Soviet period" because "the German occupation continued for a relatively short period of time".