BETHLEHEM, West Bank — Pope Francis landed Sunday in the cradle of Christianity in a symbolic nod to Palestinian aspirations for their own state, calling the stalemate in peace talks "unacceptable" and stopping briefly to pray at the Israeli separation barrier surrounding this biblical West Bank town.

The Pope issued an invitation for both Israeli and Palestinian leaders to meet at the Vatican next month, and both accepted the offer.

Jubilant Palestinians cheered Francis on the second day of his Mideast pilgrimage as he arrived for Mass in Bethlehem's Manger Square, shouting "Viva al-Baba!" or "Long live the pope!" Giant Palestinian flags in red, white, green and black and the Vatican's yellow-and-white flags decorated the square, which is home to the Church of the Nativity, built over Jesus' traditional birth grotto.

A smaller crowd waving Vatican flags also surrounded Francis as he made a brief stop en route to the square at the Israeli separation barrier surrounding three sides of Bethlehem. Francis got out of his open-topped car and bowed his head in silent prayer before the massive concrete wall that Israel says is necessary for its security and the Palestinians say has stifled life in Bethlehem and engulfed land across the West Bank.

Previous popes always came to the West Bank after first arriving in Tel Aviv, Israel. Francis, however, landed at a Bethlehem helipad from Jordan aboard a Jordanian helicopter and immediately headed into an official welcoming ceremony and meeting with Palestinian President Mahmoud Abbas.

Standing alongside Abbas, Francis declared: "The time has come to put an end to this situation which has become increasingly unacceptable."

He said both sides needed to make sacrifices to create two states, with internationally recognized borders, based on mutual security and rights for everyone.

"The time has come for everyone to find the courage to be generous and creative in the service of the common good," he said, urging both sides to refrain from any actions that would derail peace.

Later on Sunday, the offices of the Israeli and Palestinian presidents confirmed they have accepted an invitation from Pope Francis to visit the Vatican together next month.

The offices of Palestinian President Mahmoud Abbas and Israeli President Shimon Peres both said they would attend. The 90-year-old Peres, who is stepping down this summer, has been a fervent supporter of Mideast peace efforts. His decision risks upsetting Prime Minister Benjamin Netanyahu, who is angry about outreach efforts by other politicians at a time when Abbas is reconciling with the Islamic militant group Hamas.

In his remarks, Abbas voiced his concerns about the recent breakdown in U.S.-backed peace efforts and lamented the difficult conditions facing the Palestinians. He also expressed hope for peace.

"Your visit is loaded with symbolic meaning as a defender of the poor and the marginalized," he said.

Abbas listed a series of complaints against Israel, including continued settlement construction, the plight of thousands of Palestinian prisoners, Israel's control of east Jerusalem — the Palestinians' would-be capital — and Israel's construction of the "ugly wall" that encircles Bethlehem.

"We welcome any initiative from you to make peace a reality in the Holy Land," Abbas said. "I am addressing our neighbors — the Israelis. We are looking for the same thing that you are looking for, which is safety, security and stability."

Security was lax by papal standards, even for a pope who has shunned the armored popemobile that his predecessors used on foreign trips.

When Francis went to Brazil last year, a half-dozen or more bodyguards jogged alongside his open-topped car anytime he went out. With the crowds smaller in Bethlehem, only two bodyguards stood on the back of Francis' vehicle keeping watch as Palestinian police kept the crowd at bay. Francis waved and warmly smiled as his car made its way through the crowd in Manger Square, at one point holding a child passed up to him.

Palestinian officials have hailed Francis' decision to arrive first in Bethlehem, rather than Tel Aviv, and to refer to the "state of Palestine." In its official program, the Vatican referred to Abbas as the president of the "state of Palestine," and his Bethlehem office as the "presidential palace."

"The fact that he is coming straight from Jordan to Bethlehem, without going through Israel," is a tacit recognition of a Palestinian state, said Hanan Ashrawi, a Palestinian Christian who is a senior official in the Palestine Liberation Organization.

In November 2012, the United Nations General Assembly overwhelmingly recognized a "state of Palestine" in the West Bank, Gaza and east Jerusalem — lands Israel captured in the 1967 war — as a non-member observer. The recognition still has little meaning on the ground, with Israel remaining in full control of east Jerusalem, which it annexed in 1967, and the West Bank.

Israel objects to the Palestinian campaign, saying it is an attempt to bypass negotiations.

In addition to the Israeli-Palestinian conflict, Francis also sought to encourage Palestinian Christians, whose numbers have dwindled as the conflict drags on.

Currently, Christians are roughly 2 percent of the population of the Holy Land, down from about 10 percent at the time of Israel's establishment in 1948. In Bethlehem, they are less than one third of the population, down from 75 percent a few decades ago.

"I want the pope to see the situation of the Christians," said Salib Safar, 23, who studies hotel management in Bethlehem and was in Manger Square for Sunday's Mass. "The wall (separation barrier), the occupation, the pressure on our lives."

Francis acknowledged the Palestinian Christian hardship and in his homily sought to encourage the younger generations with a strong plea for children around the globe to be protected and defended from war, poverty, disease and exile as refugees.

"All too many children continue to be exploited, maltreated, enslaved, prey to violence and illicit trafficking," he said, a mural depicting the Nativity scene with the baby Jesus wrapped in the black-and-white checkered Palestinian headdress behind him. "Today in acknowledging this, we feel shame before God."

After Mass, Francis was to lunch with Palestinian families and visit a Palestinian refugee camp before arriving at Tel Aviv's Ben-Gurion airport.

At the start of his weekly Cabinet meeting, Netanyahu called the pope's visit "an opportunity to present to the world the real Israel — the advanced, modern, tolerant Israel." He said Israel guaranteed freedom of religion for all faiths.

About 8,000 police officers deployed in Jerusalem and 320 closed-circuit surveillance cameras monitored Jerusalem's old city, said Israeli police spokesman Micky Rosenfeld. Early Sunday, police arrested 26 Israelis for throwing stones at police officers and causing disturbances at a Jerusalem holy site where the pope will celebrate Mass at the end of his trip.

Rosenfeld said 150 religious Jews demonstrated to protest rumors that Israel will transfer control of the site to the Vatican. Catholics believe the site is the location of the Last Supper of Jesus, while it is revered by devout Jews as the burial spot of King David.