VATICAN CITY -- Cardinal Matteo Zuppi hand-delivered a letter from Pope Francis to U.S. President Joe Biden as part of his three-day papal mission to help promote humanitarian efforts and open avenues of peace in Ukraine.

The pope had sent the cardinal, who is archbishop of Bologna and president of the Italian bishops' conference, to Washington July 17-19 for meetings with top church and government leaders, including members of the U.S. Helsinki Commission and the Senate Prayer Breakfast.

Cardinal Zuppi and other members of a Vatican delegation went to the White House July 18 "where they were received by President Joseph R. Biden, to whom Cardinal Zuppi delivered a letter from the Holy Father, emphasizing the pope's sorrow for the suffering caused by the war," said a Vatican communique published July 19.

"The meeting, which began shortly after 5 p.m. and lasted over an hour, took place in an atmosphere of great cordiality and mutual listening," it said.

During the conversation, assurance was made of there being a "full willingness to support humanitarian initiatives, especially for children and those who are most fragile, both to respond to this urgency and to foster paths of peace," the Vatican said.

Early July 19, the Vatican delegation attended the Senate Prayer Breakfast, which is held Wednesday mornings in the U.S. Capitol for senators to meet, talk and pray together.

During this gathering, the Vatican said, "Cardinal Zuppi had the opportunity to brief the participants on the meetings he had over the various stages of his peace mission. During the meeting, appreciation was expressed for the Holy See's efforts and the responsibility of each individual to strive for peace was emphasized."

He also traveled to Russia and Ukraine in recent months to meet with church and government officials on the pope's behalf.

Cardinal Zuppi arrived in Washington the evening of July 17 and had a meeting with USCCB President Archbishop Timothy P. Broglio of Military Services at the apostolic nunciature.

"Some reflections were exchanged on the war in Ukraine and the Holy See's initiatives in support of victims and peace" during that meeting, the Vatican said.

The next morning the Vatican delegation went to the Rayburn House Office Building and met with some members of the Commission on Security and Cooperation in Europe, also known as the Helsinki Commission. This independent U.S. government commission seeks to promote human rights, military security and economic cooperation in 57 countries in Europe, Eurasia and North America.

The Vatican delegation, which included Cardinal-designate Christophe Pierre, apostolic nuncio to the United States, and Msgr. Séamus P. Horgan, charge d'affaires at the apostolic nunciature, presented to the commission "the nature and conduct of the mission entrusted to it by the pope, reflecting together on ways in which it could be made more effective."

According to Cardinal-designate Pierre, the top priority for Cardinal Zuppi in his meeting with President Biden was the repatriation of children forcibly deported from Ukraine to Russia.

The overall objective of that closed-door meeting, he told the Italian daily, La Repubblica, was "to contribute to peace and more precisely to cover the humanitarian aspects, in particular concerning children. The discussion revolved around this."

When asked if this meant that the immediate goal was facilitating the reunification of Ukrainian children with their families, the cardinal-designate said, "Yes, that is the cardinal's, and obviously the pope's, more specific goal, also because it is a more concrete issue."

"Obviously, however, the idea is to think about peace, in the complicated context that exists," he said in the interview with the newspaper, published in Italian July 19.

"The cardinal is very realistic, we try to do what is possible," Cardinal-designate Pierre said.

In general, Cardinal Zuppi's mission was "to listen and be listened to. To report on what has already happened in order to see how one can proceed," the papal nuncio said.

"This is a first step. We are realists, we know perfectly well that this is not easy. But the pope wants to contribute to (bringing) attention to a situation that will in any case have to reach an outcome," Cardinal-designate Pierre said.

Meanwhile, the White House said in a statement July 18 that President Biden shared with Cardinal Zuppi "his wishes for Pope Francis' continued ministry and global leadership and welcomed the recent nomination of a U.S. archbishop as cardinal," referring to Chicago-born Cardinal-designate Robert F. Prevost, prefect of the Dicastery for Bishops.

The U.S. president and Cardinal Zuppi "also discussed the Holy See's efforts providing humanitarian aid to address the widespread suffering caused by Russia's continuing aggression in Ukraine, as well as the Vatican's advocacy for the return of forcibly deported Ukrainian children," the White House statement said.

Pope Francis had sent Cardinal Zuppi to Washington as part of his ongoing humanitarian efforts to help Ukraine.

The July 17-19 visit is "in the context of the mission intended to promote peace in Ukraine and aims to exchange ideas and opinions on the current tragic situation and to support humanitarian initiatives to alleviate the suffering of the most affected and fragile people, especially children," the Vatican said in a communique July 17.

The cardinal visited Bucha and Kyiv in early June and met with Ukrainian officials including President Volodymyr Zelenskyy. In Moscow in late June, he met with Russian Orthodox Patriarch Kirill of Moscow; Yury Ushakov, a Kremlin foreign policy adviser and former ambassador to the United States; and Maria Lvova-Belova, Russia's commissioner for children's rights, accused by the International Criminal Court of aiding the abduction and deportation of Ukrainian children to Russia.

Cardinal Zuppi had told reporters at a book presentation in Rome July 4 that the Vatican was working on a "mechanism" to help Ukrainian children that have been taken into Russia, Vatican News reported.

"The children should be able to return to Ukraine," he said. "The first step is verifying the children and then seeing how to return them, starting with the most fragile."

"There is no peace plan (or) mediation," he said, "there is a great aspiration that the violence ends, that human lives can be saved starting with the defense of the youngest."

The cardinal said July 2 that Pope Francis' concern is to "create all opportunities to see, to listen and encourage everything that can lead toward a resolution to the conflict."

"Of course there are small openings, we must look for them," he said. "It is precisely in the darkness that the light of peace must be sought while knowing no one has a magic wand."