Pope John Paul II on Sunday decried a ``thirst for revenge'' between Israelis and Palestinians and said he was praying for the Catholic and Orthodox clergy trapped inside the Bethlehem church marking Jesus' birthplace.

``When all around the pitiless logic of arms dominates, only God can lead hearts back to thoughts of peace,'' John Paul said in his traditional weekly appearance from his window overlooking St. Peter's Square.

``Only he can give the energies that are necessary to free oneself from hate and the thirst for revenge and to take up the path of negotiations in view of the (peace) accord,'' John Paul said.

``How can one forget that Israelis and Palestinians, following the example of Abraham, believe in one God?''

The ailing, 81-year-old pope spoke in a shaky voice, slurring many of his words.

A few days earlier, the pontiff, saying news reports gave the impression of an ``unstoppable slide toward inhuman ferocity,'' asked Roman Catholics to set aside Sunday for prayers for peace in the region.

The Vatican increased its diplomatic efforts in the past few days, expressing alarm over the fighting in the Christian shrine city of Bethlehem. It has condemned both terrorism and the Israeli treatment of Palestinians.

John Paul also spoke Sunday of the ongoing standoff at the Church of the Nativity in Bethlehem.

``I particularly am thinking of, in this moment, the community of Franciscans, Greek Orthodox and Armenian Orthodox, who are living through difficult hours in the Basilica of the Nativity,'' the pope said, assuring them of his ``constant prayer.''

On Tuesday, Palestinian fighters battling Israeli troops ran for shelter inside the basilica complex and have resisted Israeli calls to come out.

Dozens of monks and a few nuns were inside the complex when the gunmen burst in.

The Vatican's missionary news service, FIDES, said an envoy of the Holy See in Israel negotiated Friday's departure of four priests from the complex.