* Rabbi, Muslim leader, will accompany pope in official delegation
* Trip is to mark 50th anniversary of Pope Paul VI visit in 1964
* Anti-Christian graffiti on walls in Jerusalem this week
The Vatican, briefing reporters on the trip, also confirmed that a rabbi and an Islamic leader will accompany Pope Francis on his trip to the Middle East in a gesture of the importance he attaches to inter-religious dialogue.
Francis will visit Jordan, the Palestinian Territories and Israel during the May 24-26 trip, his first as pope to the region.
"The pope wants an open popemobile and a normal car. The local security official took the desire of the pope into consideration," said chief spokesman Father Federico Lombardi.
"I don't think there was too much discussion about that," he said, hinting that local security officials had suggested the use of bulletproof vehicles but were over-ruled.
Francis' predecessors were driven in bulletproof limousines on their trips, whether just around Rome or abroad. Heads of state visiting the Middle East tend to use bulletproof cars.
Francis instead uses a blue Ford Focus in Rome and during his trip to Brazil last July, he was driven around Rio de Janeiro in a small silver Fiat at his own request.
At times during that trip security broke down and police were unable to control the crowds, who surrounded the car. Lombardi said he did not expect similar scenes in the Middle East because Catholics are a minority there.
Lombardi also said the Vatican was not overly concerned by threats to Christians scrawled by suspected Jewish extremists on church property in the Holy Land.
On Monday, "Death to Arabs and Christians and all those who hate Israel" was daubed in Hebrew on an outer column of the Office of the Assembly of Bishops at the Notre Dame Center in East Jerusalem.
Francis is due to meet Israeli Prime Minister Benjamin Netanyahu at the Notre Dame Center, located just outside the walls of the old city, on the last day of his trip.
Israel's Haaretz newspaper reported that Israeli security services fear that Jewish radicals might carry out a major hate crime against the Christian population or institutions to drum up media attention during the Pope's pilgrimage.
But Lombardi said he was not aware of any particular security concerns for any part of the trip.
The rabbi and Islamic leader who will be part of the official delegation are friends from Francis' days in his native Argentina, where he was archbishop of Buenos Aires before he was elected the first non-European pope in 1,300 years in March, 2013.
The pope invited them to make the trip with him in order to send what Lombardi called "an extremely strong and explicit signal" about the importance of inter-religious dialogue in the region which has seen so much conflict.
Rabbi Abraham Skorka wrote a book in 2010 with the future pope on inter-faith dialogue. The Muslim friend, Omar Abboud, is director of the Institute for Religious Dialogue in Buenos Aires.
Abboud will join the delegation in Amman and make the entire trip and Skorka will join in Bethlehem, skipping the first day because it falls on the Jewish Sabbath.
They are expected to accompany the pope to all of his events, Lombardi said, meaning Skorka will be in the Palestinian Territories and a key Islamic site in Jerusalem, while Abboud will be at the Western Wall and the Yad Vashem memorial to the Holocaust.
The trip, only the fourth visit by a pope to the Holy Land since biblical times, marks the 50th anniversary of a historic trip to the region by Pope Paul VI. Pope John Paul II visited in 2000 and Benedict XVI went in 2009.