Ukrainian President Volodymyr Zelensky has arrived at the Vatican on Saturday to meet Pope Francis.
It is the first face-to-face meeting between Zelensky and the Pope since the war began last year.
Pope Francis has been outspoken in his support for an end to the war in Ukraine.
Last year, the pontiff reportedly said during a conversation with directors of religious publications that he is not "in favor" of Russian President Vladimir Putin, but "simply against reducing complexity to the distinction between good and bad, without thinking about roots and interests, which are very complex."
"While we see the ferocity, the cruelty of the Russian troops, we must not forget the problems to try to solve them," he said at the time.
The Pope has also warned the leader of the Russian Orthodox Church, Patriarch Kirill, not to become "Putin’s altar boy."