Pope Francis called for urgent steps to end Syria's three-year-old civil war as he arrived in neighbouring Jordan on Saturday, starting a Middle East trip aimed at bringing hope to the region's dwindling Christian population.
Addressing Jordan's King Abdullah at the start of his first visit as pope to the Holy Land, Francis praised the Western-backed kingdom for its efforts to "to seek lasting peace for the entire region".
"This great goal urgently requires that a peaceful solution be found to the crisis in Syria, as well as a just solution to the Israeli-Palestinian conflict," he said.
More than 160,000 people have been killed in Syria's conflict and millions have fled to neighbouring countries, including Jordan.
After meeting King Abdullah and saying a Mass in an Amman stadium, the pontiff will meet some of those Syrian refugees in Bethany on the Jordan, the place where according to tradition Jesus was baptised, as well as others who fled violence in Iraq.
Conflict across the region, including the Arab revolts of recent years and the civil war in Syria, has accelerated a historic decline in its Christian community.
In Israel and the occupied West Bank, where the pope will travel on Sunday and Monday, more Palestinian Christians are looking to leave, accusing Israel of eroding their economic prospects and hobbling their freedom of movement.
Francis, leader of the world's 1.2 billion Roman Catholics, will also use the trip to appeal to members of all religions to work together for peace.
"Religious freedom is in fact a fundamental human right and I cannot fail to express my hope that it will be upheld throughout the Middle East and the entire world," he said.
At the Jordanian stadium where Francis was to say Mass later on Saturday, thousands of people cheered the news of his arrival in Amman. But alongside their celebrations, some expressed fears for their future in a region where Christianity is rooted.
Thamer Boulus, a 45-year-old Iraqi teacher, said he fled the city of Mosul with his family because he was receiving death threats as a Christian." I want to immigrate anywhere there is safety for me and my family. Religious extremism is threatening Christians," he said.
On Sunday morning Francis flies by helicopter to Bethlehem in the Israeli-occupied West Bank, making a six-hour visit to what the Vatican's official programme calls "the State of Palestine," a terminology Israel rejects.
In 2012, the Vatican angered Israel by supporting a vote in the United Nations General Assembly to grant Palestinians de facto statehood recognition. Israel argues such a move should only come through negotiations.
Palestinians see the pope's visit, and the fact that he is flying in directly from Jordan instead of going through Israel's security barrier from Jerusalem, as a major morale boost. Jordan, a majority of whose population is of Palestinian origin, signed a peace accord with Israel 20 years ago.
To underscore his conviction that all three great monotheistic faiths can live together in the region and help to tackle the political stalemate, Francis has enlisted a rabbi and an Islamic leader to be part of a travelling papal delegation for the first time.
The two - Rabbi Abraham Skorka and Omar Abboud, director of the Institute for Religious Dialogue in Buenos Aires - are friends from when Francis was cardinal in his native Argentina.
Their presence is "an extremely strong and explicit signal" about the importance of inter-religious dialogue in the region, Vatican spokesman Father Federico Lombardi said.
Francis, the first non-European pope in 1,300 years, will head on to Israel on Sunday night for a 32-hour visit packed with 16 events.
Threats to Christians have been scrawled by suspected Jewish radicals on Church property in the Holy Land. One read: "Death to Arabs and Christians and all those who hate Israel."
"Their writings desecrate our religious symbols. They are written on walls of churches, monasteries," Archbishop Fouad Twal, Jerusalem's top Catholic official, said in Amman.
"We want these perpetrators to be put to justice and we want to know who is behind these extremist groups. They sour the peaceful atmosphere we want to create for the Holy Father."
Israeli security forces, fearing that Jewish militants might carry out a major action against the Christian population or institutions, issued restraining orders against several Jewish right-wing activists for the duration of the pope's trip.
The last papal pilgrimage to the Holy Land was in 2009 by Francis's predecessor, Pope Benedict.