Two U.S. bishops have joined other religious leaders in asking Secretary of State John Kerry to continue "determined U.S. leadership" in negotiating for peace between Palestine and Israel.

"Indeed, no past progress toward peace has occurred in this conflict without U.S. leadership, facilitation and resolute support," said the May 20 letter to Kerry from the National Interreligious Leadership Initiative for Peace in the Middle East.

The letter was signed by more than 30 Christian, Jewish and Muslim leaders, including Bishop Richard Pates of Des Moines and Cardinal Theodore McCarrick, the emeritus Archbishop of Washington.

"A two-state agreement, in which both peoples will live in peace, security, and mutual recognition, represents the only realistic resolution of the conflict," the letter continued.

"Over time, developments on the ground and failures of leadership are making that goal more difficult to achieve."

The religious leaders professed unity in their support for Kerry's commitment to peace, saying this commitment needs his "continued, determined engagement."

"We continue to be committed to mobilizing public support of our members in synagogues, churches and mosques across the country for your efforts, and we look forward to meeting with you at an appropriate time to discuss ways we can help."

The letter comes ahead of Pope Francis' May 24-26 pilgrimage to Jordan, Palestine, and Israel, during which he will pray for peace in the Middle East.

He will arrive in Amman, the Jordanian capital, May 24 and pay a courtesy visit to the nation's king and queen, and will later address national authorities.

That afternoon he will say Mass, then visit Bethany beyond the Jordan, the site where John the Baptist was baptizing. There, Pope Francis will address refugees and the physically disabled.

The following day, Pope Francis will travel to Palestine to visit Bethlehem, meeting with Palestinian president Mahmoud Abbas, saying Mass, and praying the Regina Caeli.

He will lunch with Palestinian families at the Franciscan convent of Casa Nova, and then make a private visit to the grotto of the nativity. After this, he will be greeted by refugee children, and then depart by helicopter for Israel.

He will meet in private with Patriarch Bartholomew I, the Eastern Orthodox Archbishop of Constantinople; the two will sign a joint declaration, after which there will be a public ecumenical meeting at the Basilica of the Holy Sepulchre.

On May 26, Pope Francis will meet Jerusalem's Grand Mufti, the Sunni cleric entrusted with the city's Muslim holy places.

He will then visit the Western Wall and lay a wreath at Mount Herzl, the site of Israel's national cemetery, and then make a discourse at Yad Vashem, Israel's memorial of the Holocaust, and meet with Jerusalem's chief rabbis.

In the afternoon he will meet in private with Patriarch Bartholomew, aside the Orthodox parish on the Mount of Olives, after which he will meet with priests, religious, and seminarians at the church of Gethsemane.

Pope Francis will say Mass with the ordinaries of the Holy Land and the Papal suite at the Cenacle, and he will preach at the Mass.

In the evening, he will fly from Jerusalem to Tel Aviv, say farewell to Israel, and return to Rome.