Under former President Joe Biden, the United States lauded Zelenskyy as a hero and hammered Moscow with sanctions as Ukraine battled against advancing Russian troops.
But Trump has been critical of Zelenskyy, claiming he has subverted democracy and blaming him for starting the war that began with Russia's full-scale invasion three years ago.
"A Dictator without Elections, Zelenskyy better move fast or he is not going to have a Country left," Trump wrote on his Truth Social platform.
Zelenskyy was elected in 2019 for a five-year term and has remained leader under martial law imposed as his country fights for its survival.