VATICAN CITY (AFP) -- Pope Francis on Sunday hosts an unprecedented joint peace prayer in the Vatican with Israeli President Shimon Peres and president Mahmoud Abbas in a symbolic gesture aimed at fostering dialogue.
Abbas said he hoped the event in the Vatican Gardens, which will include Christian, Jewish and Muslim prayers and the planting of an olive tree by all three leaders, would "help Israel decide."
"The pope's invitation was courageous," Abbas said in an interview with the La Repubblica daily.
"With this prayer we are sending a message to all believers of the three major religions and the others: the dream of peace must not die," he said.
Peres, who is 90 years old and will be stepping down as president next month, was quoted by his office as saying on Sunday: "The spiritual call (for peace) is very important and affects reality.
"I hope the event will contribute to promoting peace between the two sides and throughout the world," he said, adding that the conflict is "both political and religious" and "religious leaders resonate."
He called it "an unusual call for peace."
Tensions are running high between the two sides following the formation of a new Palestinian unity government backed by the Islamist group Hamas.
Israel has since announced plans for building 3,200 new settler homes and has said it will boycott what it denounces as a "government of terror."
Peres said the Palestinian unity government was "a contradiction that can't last very long" but Abbas defended it saying: "One should never reject a chance for dialogue, internally as well."'Time to stop and breathe'
The Vatican is being realistic about the ceremony, which is unlikely to have any immediate effect.
"Nobody is fooling themselves that peace will break out in the Holy Land," said Father Pierbattista Pizzaballa, the head of the Franciscan Order in the Middle East who is organizing the historic event.
"But this time to stop and breathe has been absent for some time," he told reporters at a briefing, adding: "Not everything is decided by politics."
Francis made the offer to Abbas and Peres on his first visit as pontiff to the Middle East last month and ahead of the meeting on Sunday he reiterated his call for a Catholic Church able to "shake things up."
Speaking to thousands of followers in St Peter's Square, Francis pointed to the two colonnades around the plaza and said they were like "two arms which open to welcome but do not close again to imprison."
Francis earlier admitted it would be "crazy" to expect any Vatican mediation in the Israeli-Palestinian conflict but said prayer might help.
In a tweet from the pope's @pontifex account on Saturday, Francis said: "Prayer is all-powerful. Let us use it to bring peace to the Middle East and peace to the world."
The Vatican has defined the meeting as an "invocation for peace" but has stressed it will not be an "inter-religious prayer", which would have posed problems for the three faiths.
Peres is set to arrive at 1615 GMT followed shortly later by Abbas, with Francis welcoming them outside St Martha's Residence where he lives in the Vatican.
In the Vatican Gardens, the prayers will be recited in chronological order of the world's three main monotheistic religions, starting with Judaism, followed by Christianity, and then Islam.
The prayers from each of the three will focus on "creation," "invocation for forgiveness," and "invocation for peace" and will be read in Arabic, English, Hebrew, and Italian, the Vatican said.
Rabbi Abraham Skorka and Muslim professor Omar Abboud, two friends of Francis's from Buenos Aires who traveled with him and prayed together on his trip to the Middle East will also attend.
The Vatican said the event, which has been carefully planned in detail, was "a pause from politics."
Friday was ruled out since it is a Muslim holy day and Saturday for the same reason for the Jewish community, while Sunday is Pentecost for Catholics -- a day of celebration of the Holy Spirit considered appropriate for the event.
The choice of the Vatican Gardens as a location is also significant since it was considered the most neutral territory within the Vatican City, with none of the Christian iconography that might be seen as offensive to the other two faiths.