Recognising that the Soviet occupation of the Baltic republics was illegal would be absurd and would open a Pandora's Box of other claims, a Russian analyst close to the Kremlin said Tuesday in reaction to calls for Moscow to apologise.

"Examining the problem of the Russian occupation of the Baltics at a high level is totally absurd," Vyacheslav Nikonov told Echo Moscow radio.

This "would open a Pandora's Box and then it would be necessary to recognise the occupation of everyone by everyone," he said.

"There have been many empires in the past - British, Portuguese, Russian, Austro-Hungarian, etc," Nikonov said, and "if they all had to apologise or recognise the occupation of one part or other of the globe we would end in a very strange situation."

On Monday, EU Commission vice president Guenter Verheugen called on Moscow to tell "the truth."

"We should not hide the fact that the three Baltic states were occupied against their will for a long time," he said.

The controversy comes as Moscow preprares to host a meeting of world leaders celebrating the 60th anniversary of the end of World War II.

The three Baltic states were occupied by Stalin's Soviet Union following a Nazi-Soviet pact of 1939 and were forcibly assimilated into the Soviet Union at the end of World War II.

Estonia, Latvia and Lithuania regained independence in 1991 and joined the EU last year.