The two leaders have accepted the Pope’s request. A spokesman for President Peres said the Israeli leader “welcomes the Pope’s initiative" and that he "appreciates any effort that is being made towards achieving peace between Israel and her neighbors.”
The Jerusalem Post reported that the subject is likely to be raised in discussion when Francis meets Peres on Monday at the President’s residence and a date will be set for the meeting in the Vatican.
Meanwhile, a PLO executive committee member told CNN that the Palestinian leadership had accepted the papal invitation. Abbas' office has said the prayer meeting will take place on June 6. 
The Pope issued the invitation at the end of this morning’s Mass in Manger Square. “In this, the birthplace of the Prince of Peace, I wish to invite you, President Mahmoud Abbas, together with President Shimon Peres, to join me in heartfelt prayer to God for the gift of peace,” he said. “I offer my home in the Vatican as a place for this encounter of prayer”.
“All of us want peace,” the Pope continued. “Many people build it day by day through small gestures and acts; many of them are suffering, yet patiently persevere in their efforts to be peacemakers.
Francis said everyone, especially those “placed at the service” of their respective peoples, “have the duty to become instruments and artisans of peace, especially by our prayers.
“Building peace is difficult, but living without peace is a constant torment,” he said. “The men and women of these lands, and of the entire world, all of them, ask us to bring before God their fervent hopes for peace”.
The Pope’s initiative will have to take place soon as President Peres, who is 90 years old, steps down in July. He has served as President since 2007.
It was one of three surprises today in Bethlehem, the others being the Pope’s unexpected prayer beside the separation wall that divides Israel and Palestine, and his planned trip to Galilee, also announced at the end of the Mass.