Guterres convened an emergency meeting of the organization's Security Council after war on Gaza left over 17,400 people dead, in vast najority women and children, according to the latest toll from the health ministry in Gaza.

Guterres deployed rarely-used Article 99 of the UN Charter to bring to the council's attention "any matter which in his opinion may threaten the maintenance of international peace and security".

No one in his job had done this in decades.

Guterres is seeking a "humanitarian ceasefire" to prevent "a catastrophe with potentially irreversible implications for Palestinians" and the entire Middle East.

Some 130 UN staff members have already been killed, many with their families, Guterres said.

This represents the "largest single loss of life in the history of our organisation", he said. 

After Guterres sent his urgent letter, the United Arab Emirates prepared a draft resolution that will be put to a vote on Friday, said the delegation from Ecuador, which chairs the council this month and thus decides on scheduling issues.

The latest version of this document seen Thursday by AFP calls the humanitarian situation in Gaza "catastrophic" and "demands an immediate humanitarian ceasefire."

The Security Council is due to vote on this Arab-proposed ceasefire plan later in the day, with several other previous attempts at brokering a ceasefire having been vetoed.

The short text also calls for the protection of civilians, the immediate and unconditional release of all the captives Hamas is still holding, and humanitarian access to the Gaza Strip.

Washington, Israel's closest ally on the world stage, has said that a new resolution would not be "useful" at this stage.

Vast areas of Gaza have been reduced to a wasteland. The UN says about 80 percent of the population has been displaced, facing shortages of food, fuel, water and medicine, along with the threat of disease.

"International humanitarian law includes the duty to protect civilians and to comply with the principles of distinction, proportionality and precaution," Guterres said, calling for an immediate ceasefire.

"The laws of war also demand that civilians' essential needs must be met, including by facilitating the unimpeded delivery of humanitarian relief," he added.

The Palestinian ambassador to the UN, Riyad Mansour, expressed hope the UN will "finally" be able to call for a ceasefire, saying it is the "duty" of Security Council member states to "reject and put an end to such attacks". 

Speaking at the UN meeting, Mansour stressed it is not true that Israel does not have clear war objectives. 

"Are we supposed to pretend we don't know the objective is the ethnic cleansing of the Gaza Strip?" he introjected.

A ceasefire is the "only thing that can put end to war crimes", he says. 

The Palestinian ambassador added that all of Gaza is a target for Israel and "everyone in Gaza can be killed".

Speaking about Israel, he tells council members: "They are playing games with you, taking you for a ride. You need to wake up and see reality as it is."

The American administration has imposed restrictions on Palestinian Foreign Minister Riyad Al-Maliki limiting his ability to engage with media or respond to questions, Saudi Foreign Minister Prince Faisal bin Farhan told reporters Friday in Washington.

He was banned from publicly speaking as a prerequisite for obtaining a US visa to attend the UN meetings.

The Saudi minister said: "There is a speech ban in the visa issued by the USA."

If he talks "there will be sanctions," the minister added.

On Friday, the health ministry reported another 40 dead in strikes near Gaza City, and dozens more in Jabalia and Khan Yunis.

The Israeli occupation army orderd residents of the Jabalia, Shejaiya and Zeitun districts of Gaza City to move west.