Pope Leo XIV urged the United States and Iran to return to talks to end the war on Thursday, in a wide-ranging press conference en route home from his trip to Africa.

Leo also asserted that countries have the right to control their borders but mustn't treat migrants worse than "animals."

After a trip that was dominated by the very public back and forth between Leo and U.S. President Donald Trump over the war, the pope urged the U.S. and Iran to return to negotiations.

He called for a new "culture of peace" to replace the recourse to violence whenever conflicts arise.

He said the question wasn't whether the Iranian regime should change or not. "The question should be about how to promote the values we believe in without the deaths of so many innocents."

He revealed that he carries with him the photo of a Muslim Lebanese boy who had been killed in Israel's attacks on Lebanon. The boy had been photographed holding a sign welcoming the pope when he visited Lebanon last year.

"As a pastor, I cannot be in favor of war," he told reporters aboard his plane. "I would like to encourage everyone to find responses that come from a culture of peace and not hatred and division."

Leo was attacked by Trump on social media as "terrible" on April 12, after the pope emerged as an outspoken critic of the Iran war and the president's hardline anti-immigration policies.

Referring to the recent breakdown in peace talks, the pope said: "One day ​Iran says yes, the United States says no and vice versa. We don't know where it will go." "It has created a situation that is still chaotic ... ⁠and also there ‌is the ‌whole population of Iran, innocent people, who are suffering because ⁠of this war," he said.

Leo said he condemned "all actions that are unjust" and included capital punishment in the list.

"I condemn the taking of people's lives. I condemn capital punishment. I believe human life is to be respected and that all people, from conception to natural (death), their lives should be respected and protected.

"So when a regime, when a country takes decisions which take away the lives of other people unjustly, then obviously that is something that should be condemned," he said.

Pope Francis changed the church's social teaching to declare capital punishment immoral in all cases.

Pope decries migrants being treated 'worse than house pets'

Leo affirmed the right of countries to impose immigration controls on their borders and acknowledged that uncontrolled migration had created situations "that are sometimes more unjust in the place where they arrive than from where they left."

"I personally believe that a state has the right to impose rules for its frontiers," he said. "But saying this, I ask: 'What are we doing in the wealthier countries to change the situation in poorer countries' to provide opportunities so that people aren't compelled to leave?"

Regardless, he said migrants are human beings and deserve to be respected in their human dignity and not be treated "worse than house pets, animals."

History's first U.S. pope showed himself keenly aware of how his Africa trip had been reported and interpreted, including about his sometimes tame public addresses to African leaders who are accused of corruption or authoritarianism.

With a few notable exceptions, Leo kept his political remarks to the leaders largely diplomatic, using a language of encouragement and subtle messaging rather than headline-grabbing condemnations.

He also allowed some of the circumstances of his visit to speak louder than his words: a choreographed song and dance routine by prisoners in a country known for gross human rights abuses, or the extravagant luxury of a president's hometown in a country where more than half the population lives in poverty.

Leo insisted that his primary reason for visiting Algeria, Cameroon, Angola and Equatorial Guinea was as a pastor, to accompany his flock in their faith.

He added that the Holy See can sometimes achieve more behind the scenes via its diplomatic work, including through the release of political prisoners, than with "great proclamations criticizing, judging or condemning."