The atrocities committed by the Soviet Union that specifically targeted Ukrainians include:
- Holodomor: This was a man-made famine in Soviet Ukraine from 1932 to 1933 that resulted in millions of deaths and is considered a deliberate act of genocide against the Ukrainian people.
While "Red Terror" and "attacks on Cossacks" were also significant events related to violence and repression during the Soviet era, they are not specifically focused on targeting Ukrainians in the way that the Holodomor was. "Kulaks" refers to a class of wealthy peasants who were also targeted during collectivization, but again, this is broader and not exclusively focused on Ukrainians.
Therefore, the primary answer identifying atrocities specifically targeting Ukrainians is Holodomor.