He said people died in their homes and on the streets and were crushed by tanks in their cars "for pleasure".
Russia should be held accountable for what had happened, he said, and removed from the UN Security Council.
Horrific images of bodies in streets in towns such as Bucha have generated shock and condemnation worldwide.
After his speech by video link to the Security Council, Zelensky showed a graphic video of images of dead Ukrainians, some burned and disfigured.
