Russia has denied it illegally annexed the Baltic republics of Latvia, Lithuania and Estonia in 1940.
The Baltic-Russian row has escalated ahead of VE Day
It has also rejected demands to admit illegally occupying the three countries at the end of World War II.
A Kremlin spokesman said Soviet troops were deployed with the agreement of the Baltic governments of the time.
Correspondents say the annexation issue has provoked a major diplomatic row as Russia prepares to host celebrations to mark the end of World War II in Europe.
Soviet authority was established in the Baltics in 1940.
German forces then held the states from 1941 until the Soviet army returned in 1945.
EU and US pressure
Russia has made defiant remarks on the issue of the occupation.
"There was no occupation. There were agreements at the time with the legitimately elected authorities in the Baltic countries," the Kremlin's European affairs chief Sergei Yastrzhembsky said on Thursday.
The EU - which now includes the three Baltic republics - and the US want Moscow to recognise that the Red Army occupied large parts of Eastern Europe after the retreat of the Nazis at the end of World War II.
European Commission Vice-President Guenter Verheugen urged Moscow earlier this week to admit the illegality of Soviet rule in the Baltics.
US President George Bush said in a TV interview to be broadcast on Thursday that he would remind Russian President Vladimir Putin about the Soviet occupation of the Baltics when they met in Moscow next week for VE Day celebrations.
The heads of two of the three Baltic states, Estonia and Lithuania, are boycotting the events in Moscow, but Latvian leaders have said they will attend.
On Wednesday, Russian Defence Minister Sergei Ivanov suggested the defeat of Hitler far outweighed the USSR's long occupation of Eastern Europe after World War II.