Mayor Eric Adams, who talks often about his faith, acknowledged on Saturday that he had felt some uncertainty — if not anxiety — about meeting Pope Francis.
But at the Vatican, as Mr. Adams stooped before the pope, he felt any disquiet he had wash away. Pope Francis placed his hand on the mayor’s right arm. Then, the two shook hands.
“I think that some people have a level of aura and energy and the ability to just calm people,” said Mr. Adams, who is Christian but not Catholic. “I think that’s what he possessed. In my prayers, I thank God for having the opportunity this morning.”
The meeting came on the second day of a three-day trip to Italy for Mr. Adams, who said he is trying to better understand the global conflicts that touch New York. The visit came as the mayor, who is up for re-election next year, faces difficulties in New York City, including lagging poll numbers and a federal investigation into his campaign fund-raising.
There was no specific agenda for the meeting between the mayor and the pope, which came as the pope met with participants of a conference about peace. But after the meeting, Mr. Adams said the two spoke about conflicts in Haiti, Africa and the Middle East. They talked about the Foundation to Combat Anti-Semitism, a nonprofit created by Robert Kraft, the owner of the N.F.L.’s New England Patriots.
“He responded affirmatively and said: ‘Eric, please pray for me as well,’” the mayor said.
Mr. Adams and the pope took part in the World Meeting on Human Fraternity, a conference organized by the Fratelli Tutti Foundation, which was founded by Pope Francis, that brought Nobel laureates and celebrities to Rome to promote peace.
“War is a deception, as is the idea of international security based on the deterrent of fear,” Pope Francis told people attending the conference, who gathered at the Vatican on Saturday. “Ensuring lasting peace requires a return to a recognition of common humanity and to place fraternity at the center of peoples’ lives.”
Mr. Adams said it was a “sacred moment for me just to have an opportunity to hear from Pope Francis as he leads the world on the most important issues of our time, from the global refugee crisis to climate change, to the journey toward peace.”
The mayor often speaks publicly about how his Christian faith informs the way he governs. He has said he does not believe in the separation of church and state and has described himself as a “prayer warrior.” He has even criticized the removal of prayer in schools.
On Saturday, the mayor made several stops in Rome. After the meeting, he showed up at the formerly dilapidated Piazza di San Cosimato in a New York Knicks playoff hat and a black polo shirt. Then, he went to the World Meeting on Human Fraternity conference.
Mr. Adams toured the piazza with the mayor of Rome, Roberto Gualtieri, to hear about the work of Rome Cures Rome, a civic association that helps clean up the area. The two mayors also painted over graffiti on a building there.
“Government can’t do it all,” Mr. Adams said as he painted, speaking in favor of the role civic groups can play.
Mr. Adams has said part of his goal on the trip is to learn how to deal with New York’s problems from a city like Rome. Both Mr. Gualtieri and Mr. Adams, in speeches before the World Meeting on Human Fraternity on Saturday, emphasized the bonds between cities and the shared crises like homelessness and helping migrants seeking asylum.
“The issues are basically the same,” Mr. Gualtieri told the audience.
Mr. Adams, addressing the crowd at the piazza, said that “New York is the Rome of America,” echoing a phrase he uses often when describing other cities.
Earlier in his trip, Mr. Adams visited the Colosseum and saw the construction site of a Metro station there. He also toured the Sistine Chapel and the Vatican Museums.
Mr. Adams attended the closing ceremony of the conference on Saturday night at St. Peter’s Basilica. On Sunday, Mr. Adams is expected to tour a site that is providing services for migrants. He will return to New York City on Monday.
Mr. Adams’s celebration of the pope’s antiwar message provoked criticism from some in New York City, who say the mayor has not spoken out enough on ending Palestinian suffering during Israel’s war in Gaza.
“The response we need is a leader who will show up for Israeli and Jewish communities and Palestinian and Muslim communities,” said Shahana Hanif, a Muslim councilwoman from Brooklyn.
Mr. Adams said people have thanked him for his stance on Palestine and Israel.
“I’m comfortable in how I’ve taken a strong stance that children and innocent people should not die globally,” he said. “I’m not the type of person that is inconsistent in that message.”
Elisabetta Povoledo contributed reporting.
