Israeli Prime Minister Benjamin Netanyahu on Tuesday received a letter from president Mahmoud Abbas about the moribund peace process, as he met in Jerusalem with two Palestinian officials, his office said.

The brief meeting was described by the Palestinians as "serious," with both sides saying Netanyahu would reply with his own letter to Abbas "within two weeks."

Top officials from the United States, Russia, United Nations and European Union will meet Monday to discuss deadlocked efforts to end the Israel-Palestinian conflict, the U.N. said.

It will be the first top level meeting of the diplomatic Quartet in six months and comes amid a new flare-up in violence which has left at least 21 Palestinians dead in Israeli raids on the Gaza Strip since Friday.

Israeli air strikes on Gaza killed 15 Palestinians, including a militant group chief, medics said on Saturday, in the deadliest 24 hours in the border area in more than three years.

A Palestinian riding a motorcycle was killed and two others were wounded in an Israeli air raid close to the southern town of Rafah near the border with Egypt on Saturday afternoon, Palestinian medics said.

About 2,000 mourners, some firing automatic rifles into the air, marched on the outskirts of Jerusalem on Saturday with the body of a Palestinian shot dead by Israeli troops.

Tareq Arumi, 23, was killed in one of a string of clashes on Friday between Israeli forces and Palestinian protesters angry over violence in the flashpoint Al-Aqsa mosque compound in Jerusalem's Old City.

Palestinian President Mahmoud Abbas and his rival Hamas leader Khaled Meshaal on Thursday postponed talks on forming a unified government, a Fatah official said, in a further delay to ending an almost five-year rift.

The official with the Abbas-led party said the talks were postponed "because Hamas continues to prevent the election committee from registering voters in Gaza," the Islamist-ruled Palestinian territory.

Palestinian President Mahmoud Abbas arrived in Cairo on Wednesday for talks with Hamas chief Khaled Meshaal on the formation of a national unity government, the official MENA agency reported.

The long-time rivals have been struggling to implement the terms of a reconciliation deal signed in Cairo in May, which calls for the formation of an interim government of independents to pave the way for presidential and legislative elections within a year.

President Mahmoud Abbas said on Saturday that the next Palestinian government will respect agreements signed by the PLO, a reference to the peace accords with Israel.

"The next government will remain committed to the obligations and agreements signed by the Palestine Liberation Organization," Abbas said, the Palestinian news agency WAFA reported.

A Palestinian in Gaza died early Sunday after being wounded in a series of retaliatory Israeli airstrikes, Gaza medical sources said.

The fatality was identified as Abdel Karim Zatuniya, an elderly man serving as a guard at the barracks in the Zeitun area, south-east of Gaza city, who was wounded in an airstrike late Saturday night in which four other people were wounded. No militant faction in Gaza announced Zatuniya a member.

Middle East peace Quartet envoy Tony Blair met Palestinian president Mahmoud Abbas in Amman on Saturday to discuss the stalled peace process, Blair's office said.

A statement said Blair reaffirmed to Abbas the Quartet and international community's "commitment" to the peace process, "and the need to launch credible and serious negotiations in order to reach the two-state solution."

The Palestinian leadership on Thursday endorsed the latest agreement between the heads of Fatah and Hamas and called for preparations for elections to be speeded up.

Palestinian President and Fatah head Mahmoud Abbas and Hamas leader Khaled Meshaal inked an accord in Doha on Monday placing Abbas at the head of an interim government to supervise the run-up to elections later this year.