Some verbs that normally take an Accusative object require that the object be in the Genitive, when the action is negated.
— ТІ вќдишь на столљ рємки (Acc.)? "Do you see the (small) wine glasses?"
— Гдљ рємки? Ї не вќжу на столљ рємок (Gen.). "Where are the wine glasses? I don't see wine glasses on the table."
Often, one can use either Genitive or Accusative with negated verbs that otherwise take Accusative:
Ї не љм лџк (Acc.). I don't eat onions.
Ї не љм лџка (Gen.). (Same meaning.)