An Israeli settler was stabbed to death by a knife-wielding Palestinian in the northern West Bank on Tuesday, in the first fatal anti-Israeli attack in the territory in 18 months, officials said.

The attack, which took place near Tapuah junction south of Nablus, prompted clashes between Jewish settlers and Palestinians in a nearby village, security sources said.

Pope Francis called on Tuesday for Israel and the Palestinians to "resume negotiations" and "take courageous decisions", the Vatican said in a statement, after a meeting between the pontiff and Israeli President Shimon Peres.

"A speedy resumption of negotiations between Israelis and Palestinians is hoped for," it said.

A rebel victory in Syria's civil war would be the most positive outcome for Israel despite fears of instability and a stronger jihadist presence on the Golan should the regime collapse, analysts say.

The Syrian conflict has increasingly affected the Jewish state, as alarm mounts over the deployment of President Bashar Assad's chemical weapons arsenal and the potential for it to fall into the hands of non-state militant groups.

An Israeli air strike on Gaza City killed one person and wounded another on Tuesday, Gaza's Hamas-run health ministry said.

"A man in his 20s was martyred and another injured in an Israeli air strike... in Shati refugee camp in western Gaza City," health ministry spokesman Ashraf al-Qudra told Agence France Presse.

Israel on Tuesday welcomed a shift in the terms of the 2002 Arab Peace Initiative following top-level talks in Washington, with the proposal now endorsing the idea of mutually-agreed land swaps with the Palestinians.

The principle of land swaps has been affirmed by Israel and the Palestinians in previous rounds of talks but has never formed part of the Saudi initiative.

A former Israeli defense minister has said that Syria's chemical weapons are "trickling" to Hizbullah. But Israeli officials said they did not have any evidence about the alleged transfer.

Binyamin Ben-Eliezer, a retired general who is now a lawmaker from the opposition Labor party, told The Associated Press on Monday: "The process of weapon transferal to Hizbullah has begun."

Israeli president and Nobel peace laureate Shimon Peres left for Rome on Monday for talks with Pope Francis and the new Italian government, his office said.

"I intend to personally invite Pope Francis for an official state visit to Israel and to strengthen the good relations that already exist between Israel and the Vatican," a statement quoted Peres as saying before his departure.

Palestinian Christians near Bethlehem on Monday urged Pope Francis to speak up against an Israeli decision to build its controversial separation barrier on a route they say would cut off their community.

"We cry to your Holiness with a feeling of despair and urgency in order to keep alive our hope that justice and peace is still possible," said an open letter from the Christians of Beit Jala, a town near the West Bank city of Bethlehem.

A Lebanese security official denied on Monday that a drone downed by the Israeli air force off the northern coast of Israel had been sent from Lebanon.

The official, who was not identified, told An Nahar newspaper that Israel rushed to the conclusion that Hizbullah was behind the unmanned aircraft (UAV) that the Israeli military said was intercepted five nautical miles off the coast of Haifa last Thursday.

Military action in response to Syria's suspected use of chemical weapons would be "very, very complex," the Israeli ambassador to the United States said Sunday.

Michael Oren said air strikes on chemical weapons bases pose a risk of collateral damage to civilians if agent is dispersed, and under international law the attacker would be at fault.