Global opposition to the humanitarian crisis in Gaza has been growing, with world leaders and aid groups warning that a looming Israeli invasion of the southernmost city of Rafah would lead to massive civilian causalities.

Palestinian president Mahmoud Abbas appealed to the United States on Sunday to stop Israel from invading Rafah, which he said would be "the biggest disaster in the history of the Palestinian people".

The US -- Israel's main ally and weapons supplier -- was the only nation capable of preventing Israel from "committing this crime", Abbas told a global economic summit in Saudi Arabia.

Hamas said on Saturday it was studying a new Israeli counterproposal for truce and captive release, a day after media reports said an Egyptian delegation was in Israel in a bid to jump-start stalled negotiations.

Egypt, Qatar, and the United States have been trying to mediate a new truce ever since a one-week halt to the fighting in November saw 80 Israeli captives exchanged for 240 Palestinians held in Israeli prisons.

Hamas has previously insisted on a permanent ceasefire -- a condition that Israel has rejected.

However, the Axios news website, citing two Israeli officials, reported that Israel's latest proposal includes a willingness to discuss the "restoration of sustainable calm" in Gaza after captives are released.

It is the first time in the nearly seven-month war that Israeli leaders have suggested they are open to discussing an end to the war, Axios said.

Abbas spoke at a World Economic Forum (WEF) summit that opened Sunday in Riyadh, which US Secretary of State Antony Blinken and high-ranking officials from other countries trying to broker a ceasefire are also due to attend.

The Palestinian president stressed the need to reach a political solution that unites the Gaza Strip, the West Bank, and Jerusalem in an independent Palestinian state.

In his speech before the Forum, he expressed his fear that Israel, after its war on the Gaza Strip, would turn to the West Bank to displace its people towards Jordan.

A senior Qatari official has urged both Israel and Hamas to show “more commitment and more seriousness” in cease-fire negotiations in interviews with Israeli media.

The interviews with Haaretz and Israeli public broadcaster Kan, Qatar’s Foreign Ministry spokesperson Majed al-Ansari expressed disappointment in both Israel and Hamas, saying each side has made its decisions based on political interests and not with the good of civilians in mind.

“We were hoping to see more commitment and more seriousness on both sides,” he told Haaretz.

He did not reveal details of the current state of the talks, other than to say they have “effectively stopped,” with “both sides entrenched in their positions.”

A senior Hamas official told AFP on Sunday that the group would deliver its response to Israel's latest counterproposal for a ceasefire on Monday in Egypt.

"A Hamas delegation headed by Khalil al-Hayya will arrive in Egypt tomorrow... and deliver the movement's response" to the Israeli proposal during a meeting with Egyptian officials, said the official who declined to be named.

Children under the rubble

While there is no Israeli participation, other key players will discuss the truce talks and humanitarian situation in Gaza, WEF president Borge Brende said.

There was "some new momentum now in the talks around the hostages, and also for... a possible way out of the impasse we are faced with in Gaza," he said.

The Palestinian health ministry said Sunday that Israel has killed at least 34,454 people in Gaza during nearly seven months of the Israeli genocidal war on the Strip.

The tally includes at least 66 deaths in the past 24 hours, a ministry statement said, adding that 77,575 people have been wounded since the war broke out on October 7.

In central Gaza, Mohammed al-Hattab said he found his one-year-old boy in the rubble after an Israeli air strike hit the Nuseirat refugee camp over the weekend.

The boy is being treated for a fractured skull, while his two-year-old daughter's face was "completely disfigured" in the strike, he told AFP.

Israel carried out air strikes and shelling in Gaza overnight, hitting three houses in the southern city of Khan Younis, an AFP correspondent said Sunday, also reporting strikes on Gaza City and Rafah.

Most of Gaza's population has taken refuge in Rafah, according to the UN, many in makeshift shelters after fleeing violence elsewhere.

Despite international outcry, Israel has vowed to invade the city.

On the side of a tent in Rafah on Saturday, a Palestinian wrote a message to the thousands of protesters on US university campuses.

"Thank you, students in solidarity with Gaza, your message has reached," it read.

UN humanitarian agency OCHA has warned that "famine thresholds in Gaza will be breached within the next six weeks" if a massive amount of food aid does not reach the territory.

A British ship set sail towards Gaza on Saturday which is planned to house hundreds of US troops building a temporary floating pier off the coast to help deliver aid.