Pope Francis
Pope FrancisReuters

Pope Francis on Wednesday slammed the deadly attack on a Jerusalem synagogue and urged Israelis and Palestinians to take the "courageous decisions" needed to achieve reconciliation.

Against a backdrop of fears the conflict could be entering a new phase of sectarian violence and Israel's warning of a tough response to the massacre at the synagogue in Har Nof, the Argentinian pontiff appealed for restraint and dialogue.

"I have followed with concern the alarming increase in tension in Jerusalem and other zones of the Holy Land and the unacceptable incidents from which even places of worship have not been spared," he said at his weekly general audience.

"From the bottom of my heart I appeal to the parties involved to put an end to the cycle of hate and violence and to take courageous decisions for reconciliation and peace.

"Building peace is difficult but without peace life is torment."  

Five people were killed in the attack Tuesday morning, when two Arab terrorists stormed the Kehilat Yaakov synagogue armed with a gun and meat cleavers during morning prayers. Four worshipers were murdered as they prayed before the terrorists were shot dead in an exchange of fire with police. One policeman, Zidan Seyf, was critically wounded and died of his injuries later Tuesday night. 

Israeli Prime Minister Binyamin Netanyahu has promised a harsh response and it appeared Wednesday that a crackdown was under way in eastern Jerusalem with Israeli forces demolishing the home of the terrorists responsible for a previous attack which killed two Israel civilians, including a three-month-old baby girl.

Abdelrahman Shaludi drove his car into a group of pedestrians standing at a Jerusalem light rail stop in the capital's Ammunition Hill, murdering baby Chaya Zisel Braun and 22-year-old student Karen Jemima Mosquera, and injuring several others, before being shot dead by police.

AFP contributed to this report.