Putin's February 2022 invasion of Ukraine sparked a major European war after eight years of conflict between Ukrainian forces and pro-Russian factions.
Early result means Putin, 71, will easily secure new six-year term that would enable him to overtake Josef Stalin and become Russia's longest-serving leader.
Zelensky's comments followed anger over a suggestion by Pope Francis at the weekend that "the strongest are those who see the situation, think about the people.