THE Russian parliament agreed in principle a declaration that Soviet dictator Joseph Stalin personally ordered the Katyn massacre of Polish officers in World War II.

The lower house, the State Duma, agreed a text that breaks several years of official reluctance to admit that Stalin and the Soviet leadership ordered the killing of thousands of Polish officers in 1940.

"Materials that for many years have been kept in secret archives and have now been published not only show the extent of this terrible tragedy but show that that Katyn crime was carried out on the direct orders of Stalin and other Soviet leaders," the declaration stated.

The text was agreed at an unusually stormy session of the Duma, despite virulent opposition from the minority Communist Party, many of whose officials still insist the massacre was carried out by the Nazis.

"This declaration is, without exaggeration, of historic importance," the head of the Russian Duma's foreign affairs committee Konstantin Kosachev was quoted as saying on the website of ruling party United Russia.

The Soviet Union initially blamed the Katyn massacre on the Nazis and its guilt was only admitted by ex-Soviet leader Mikhail Gorbachev just before the collapse of the Soviet Union in 1990.

However, after this the crime was rarely acknowledged in public until the April 10 air crash that killed Polish President Lech Kaczynski brought a new rapprochement in Warsaw-Moscow ties.