UN chief Antonio Guterres pleaded Saturday for a "humanitarian ceasefire" in the war between Israel and Hamas militants that has devastated much of Gaza, demanding "action to end this godawful nightmare".

Addressing a Cairo summit that ultimately proved fruitless, according to Arab diplomats, Guterres said the Palestinian enclave of 2.4 million people was living through "a humanitarian catastrophe" with thousands dead and more than a million displaced.

The latest bloodshed began on October 7 when Hamas militants killed at least 1,400 people, mostly civilians who were shot, mutilated or burnt to death on the first day of the raid, and took more than 200 hostages, according to Israeli officials.

Israel has hit back with a relentless bombing campaign, killing more than 4,300 Palestinians, mainly civilians, according to Gaza's Hamas-run health ministry, and cut off supplies of water, electricity, fuel and food.

According to Arab diplomats who spoke to AFP on condition of anonymity, the meeting in Cairo failed to reach an agreement, with Western representatives seeking "a clear condemnation placing responsibility for the escalation on Hamas", which Arab leaders refused.

The Western officials also wanted to call for the release of those held by Hamas.

Egypt's presidency instead released a statement — drafted with the approval of Arab attendees, the diplomats said — saying the war had laid bare "a defect in the values of the international community".

World leaders have long "sought to manage the conflict, and not end it permanently, by proposing temporary solutions and palliatives that do not live up to even the lowest aspirations of a suffering people", the statement read.

In response, Israel bemoaned the lack of a condemnation of what it called "Islamic terror" that endangered the region and entire world.

"It is unfortunate that even when faced with those horrific atrocities, there were some who had difficulty condemning terrorism or acknowledging the danger," a foreign ministry statement said.

"Israel will do what it has to do and expects the international community to recognise the righteous battle."

'Global silence' 

In the opening session, Guterres had said "the grievances of the Palestinian people are legitimate and long" after "56 years of occupation with no end in sight" but stressed that "nothing can justify the reprehensible assault by Hamas that terrorised Israeli civilians".

He then stressed that "those abhorrent attacks can never justify the collective punishment of the Palestinian people".

In the meeting which also included the leaders of the United Arab Emirates, Spain and Italy, Jordan's King Abdullah II called for "an immediate end to the war on Gaza" and condemned what he labelled "global silence" on Palestinian death and suffering.

"The message the Arab world is hearing is loud and clear: Palestinian lives matter less than Israeli ones. Our lives matter less than other lives," he charged.

"The application of international law is optional. And human rights have boundaries — they stop at borders, they stop at races, and they stop at religions."

The summit came on the day a first convoy of aid trucks rumbled into southern Gaza, which Guterres said needed to be rapidly scaled up, with "much more" help sent through.

The UN has said that about 100 trucks per day are needed to meet worsening needs in Gaza.

The Palestinians need "a continuous delivery of aid to Gaza at the scale that is needed", the UN chief told the Cairo "Summit for Peace".

'We will not leave' 

Egypt's President Abdel Fattah al-Sisi argued that the "only solution" to the Israeli-Palestinian conflict is "justice" and said that "Palestinians must realise their legitimate rights to self-determination" and have "an independent state on their land".

Abbas stressed his demand for a two-state solution and an "end to Israel's occupation" and rejected what he has warned could be a "second Nakba" — a reference to the more than 760,000 Palestinians who fled or were expelled from their lands during the creation of the state of Israel in 1948.

"We will not leave," he repeated three times at the end of his speech.

Cairo and Amman have repeatedly rejected calls for large numbers of refugees to enter Egypt from Gaza, warning that the "forced displacement" would lead to the "eradication of the Palestinian cause".

Egypt and Jordan were the first Arab states to normalise relations with Israel, in 1979 and 1994 respectively, and have since been key mediators between Israeli and Palestinian officials.

Turkey's foreign minister Hakan Fidan urged for the current conflict to become, "rather than a regional conflagration, a breeding ground for a just and lasting peace".

He also condemned "unconditional military aid to Israel which only serves to maintain the occupation", while Saudi Foreign Minister Prince Faisal bin Farhan condemned the failure of the UN Security Council to pass a resolution calling for a ceasefire after a US veto.