Mr Zelensky issued his warning during a live question and answer session in Munich on Friday (14 February).
He warned: “I think that he [Vladimir Putin] is preparing the war against Nato countries next year. I think so, but I don’t know, I don’t have 100 per cent. God bless, we will stop this crazy guy.”
His warning comes hours after the Ukrainian president accused Russia of a drone attack on Chernobyl nuclear power plant in Ukraine that damaged a radiation shelter.