The Republican presidential candidate in the fall's US election has said several times that he would only need days to end the war, and Trump is reported to have suggested pressuring Ukraine to give up the occupied Crimean peninsula and the partially occupied Donbass region.
And during this week's election debate Trump refused to answer whether he wants Ukraine to win the war.
Does Not Understand Everything
Volodymyr Zelenskyj says in an upcoming CNN interview that the messages "make us naturally nervous" but that they should be taken with a grain of salt.
I don't understand it today because I can't know all the details, what he means and doesn't. But they are in an election campaign and the messages then are election messages. Sometimes they don't have much to do with reality, he says in released clips.
The two spoke on the phone in July, and Trump promised then, according to Zelenskyj, to stand behind Ukraine if he becomes president.
Trump himself said at the time that he would ensure Russia ends its war of aggression against Ukraine.
"Both sides will be able to gather and negotiate an agreement that ends the violence and paves the way for prosperity," he wrote on his platform Truth Social.
Optimist
Trump has also criticized the US's multi-billion support to Ukraine and said in a speech in June that Zelenskyj "is perhaps the best salesman politics has ever seen".
A possible Trump victory in the presidential election has also raised concerns among allies in Europe about the US's continued support for Ukraine.
But Zelenskyj is optimistic.
He will support us, he says in the CNN interview that will be broadcast in its entirety on Sunday.