Ukraine plans to open a formal investigation into a Soviet-era famine that killed millions of people to see if it can prove the famine was an act of genocide.

The 1932-33 famine was engineered by Soviet dictator Josef Stalin to force peasants to give up their private plots of land and join collective farms.

Ukraine, which has rich farmland, suffered the most of all Soviet regions and President Viktor Yushchenko has led efforts to win international recognition of the tragedy as an act of genocide against the Ukrainian nation.