VATICAN CITY (CNS) -- After literally hundreds of public prayers for peace in Ukraine and 443 days after Russia launched an all-out war on the Eastern European country, Pope Francis welcomed Ukrainian President Volodymyr Zelenskyy to the Vatican.

The topics of the conversation May 13 included "the humanitarian and political situation in Ukraine caused by the ongoing war," the Vatican press office said.

Pope Francis assured the president of "his constant prayers, evidenced by his many public appeals and continuous invocation to the Lord for peace since," the statement continued.

"Both agreed on the need for continued humanitarian efforts to support the population," the Vatican said. And "the pope particularly stressed the urgent need for 'gestures of humanity' toward the most fragile people, the innocent victims of the conflict."

Zelenskyy, in a tweet after the meeting, said he was grateful for the pope's "personal attention to the tragedy of millions of Ukrainians."

But he also said he asked the pope "to condemn Russian crimes in Ukraine. Because there can be no equality between the victim and the aggressor."

Earlier that morning, in a speech to new ambassadors to the Vatican, Pope Francis seemed to indirectly address criticisms, including by many Ukrainians, of his attempts not to demonize and isolate Russia.

Having no "political, commercial or military aims," the pope said, the Vatican operates on the world stage "through the exercise of a positive neutrality. Far from being an 'ethical neutrality,' especially in the face of human suffering, this affords the Holy See a certain standing in the international community that allows it to better assist in the resolution of conflicts and other matters."

Zelenskyy also tweeted that he spoke to the pope "about our 'peace formula' as the only effective algorithm for achieving a just peace," and he said asked the pope to support it. Among other things, the formula insists on the withdrawal of Russian forces from all of Ukraine's territory and proposes Russia pay reparations for the damage inflicted on Ukrainian infrastructure.

As he often does with formal visits in the afternoon, the pope met with the president in his studio at the back of the Vatican audience hall rather than in the library of the Apostolic Palace.

Photos from Vatican Media showed Pope Francis going to the door of the building to welcome the president as soon as he stepped from his car.

While the Vatican did not allow live coverage of the visit, a Vatican video clip showed Zelenskyy placing a hand on his chest and telling the pope, "It's an honor."

Once they were in the studio, the pope told Zelenskyy, "Thank you for this visit."

The Vatican press office said the pope and president spoke privately for 40 minutes before they were joined by Zelenskyy's entourage for the presentation of gifts.

The president gave the pope a poster, resembling a Marian icon, but with a dark figure where the child Jesus would normally be. Titled "Loss 2022-58," it commemorates the 243 children who died during the first 58 days of the war, said an accompanying explanation. In addition, Zelenskyy gave the pope a collage painted on the bullet-dented plate of a soldier's bulletproof vest.

Pope Francis gave the president a bronze olive branch. The accompanying note referred to the biblical story of Noah and the flood, referring to the olive branch as a symbol of peace and of renewal after destruction.

After meeting the pope, Zelenskyy and his entourage also met with Archbishop Paul R. Gallagher, Vatican foreign minister. Cardinal Pietro Parolin, Vatican secretary of state, was out of town.

Pope Francis and Zelenskyy had spoken on the phone at least twice in the first month of the war, which began Feb. 24, 2022, but had not seen each other in person since early 2020.

The president and members of his government repeatedly have invited Pope Francis to visit Kyiv, but the pope consistently has said he would not visit the Ukrainian capital unless he also could visit Moscow on a mission of peace. Russian officials continue to say the time is not right.

Zelenskyy also met in Rome with Prime Minister Giorgia Meloni and President Sergio Mattarella, thanking them both for their support of Ukraine and for the military assistance Italy is providing.

Pope Francis has consistently condemned the arms trade, including in remarks since the Russian invasion, leading many to think he opposed the efforts of the European Union and NATO to help Ukraine defend itself.

But, when asked specifically about Ukraine buying or receiving weapons, he said in September, "This is a political decision, which can be moral -- morally acceptable -- if it is done according to the conditions of morality, which are manifold. ... But it can be immoral if it is done with the intention of provoking more war or selling weapons or discarding those weapons that are no longer needed."

A few hours before Pope Francis welcomed Zelenskyy to the Vatican, a message on Pope Francis' Twitter account read: "May #OurLadyOfFatima, the mother of Jesus and our own mother, help us create paths of encounter and dialogue that lead toward peace, and grant us the courage to trod them without hesitation."

May 13 is the feast of Our Lady of Fatima, the anniversary of the day in 1917 when three Portuguese children said they first saw Mary. In the monthly apparitions, which continued until Oct. 13, 1917, Mary encouraged the children to pray for peace and, they said, for the conversion of Russia.

Pope Francis, at his general audience May 3, said, "I recall the request of Our Lady of Fatima to the three shepherd children: 'Pray the rosary every day for peace in the world and an end to the war.' I, too, ask you to pray the rosary for peace."

The meeting between the pope and Zelenskyy came two weeks after Pope Francis told reporters the Holy See is working on a project related to peace between Russia and Ukraine, but he could not talk about it yet.

"There is a mission underway that is not public yet; when it is public, I will tell you about it," Pope Francis told reporters traveling with him from Budapest, Hungary, back to Rome April 30.

Ukrainian and Russian officials denied knowing anything about it. But Cardinal Parolin, Vatican secretary of state, insisted they did. And, speaking to reporters May 10, he said progress was being made, "but of course at the confidential level. However, the thing I think has been explained, and I think it will go forward."

Pope Francis has said the Vatican has been involved in successfully mediating prisoner-of-war exchanges between Ukraine and Russia and, in late April, when Ukrainian Prime Minister Denys Shmyhal visited the pope at the Vatican, he asked for the Vatican's help in returning to Ukraine children taken by force to Russia.

The Ukrainian government's "Children of War" website claimed, as of May 13, that 19,393 children had been forcibly removed from Ukraine and taken to Russia.

Zelenskyy, in his tweet, he also spoke to the pope "about tens of thousands of deported Ukrainian children. We must make every effort to return them home."