Ukraine on Wednesday blamed Soviet leaders for a famine that killed millions of people in 1932-33 and published documents it said "unequivocally" proved its case, part of its campaign to get the tragedy recognized as genocide, according to The Canadian Press.

The national security service published archive documents it said proved that Soviet leader Josef Stalin and his subordinates were responsible for the famine.

The scale of the death toll is contested. Some historians believe 3.5 million perished in what is known in Ukraine as "Holodomor," or "death by hunger", while the country`s leaders say up to 10 million died.

The issue has become a sore point in Ukraine`s uneasy relations with Russia.

Russia made no official comment Wednesday. In April, the lower house of parliament passed a resolution saying the famine should not be considered genocide.

The documents included orders to punish those resisting collectivization and withholding agricultural products as well as details on campaigns to root out Ukrainian nationalist organizations.

The famine was masterminded by Soviet authorities to force peasants across the Soviet Union to give up their private plots and join collective farms. The measure was particularly calamitous in Ukraine, the breadbasket of the Soviet state.

Moscow says it was not an act of genocide because other ethnic groups, such as Russians and Kazakhs, also suffered. As the Soviet Union`s legal successor, Russia is also concerned about the possibility of legal action or having to pay reparations.

Historians in Ukraine and the West are divided on whether the famine was an act of genocide. Some are convinced the famine targeted Ukrainians as an ethnic group. Others argue Soviet authorities set out to eradicate private landowners as a social class.

The Canadian Press