The Pope and Ukrainian President Volodymir Zelensky met at the Vatican on Saturday.
In the private meeting, which lasted around 40 minutes, the pair discussed the humanitarian and political situation in Ukraine, which has been at war with Russia for over a year.
The Pope and Zelensky exchanged gifts, with the Ukrainian president receiving a bronze sculpture of an olive branch representing peace.
Zelensky gifted the Pope with two works of art, one called "Loss", representing the children who have died in the conflict, and the other made from a bulletproof plate.
During the meeting, the Pope said he was praying for Ukraine and spoke of the importance of "gestures of humanity" towards the most vulnerable, Vatican News reports.
In a tweet after the meeting, Zelensky said he had spoken to the Pope "about the tens of thousands of deported (Ukrainian) children".
"We must make every effort to return them home," he wrote.
Zelensky also thanked the Pope for "his personal attention to the tragedy of millions of Ukrainians".
The meeting took place during Zelensky's visit to Rome where he met with Italian Premiere, Giorgia Meloni, and President Sergio Mattarella.