A UN aid agency says 6,000 trucks carrying food and aid are waiting to enter Gaza, which is being ravaged by mass starvation, as Israel and the US pull their teams out of ceasefire talks in Qatar.
The path ahead for ceasefire negotiations is now unclear.
"While the mediators have made a great effort, Hamas does not appear to be coordinated or acting in good faith," US envoy Steve Witkoff posted on X.
"We will now consider alternative options to bring the hostages home and try to create a more stable environment for the people of Gaza."
An Israeli official told Reuters that Hamas's response to the most recent ceasefire proposal "does not allow for progress without a concession" by the group, but that Israel intended to continue discussions.
[TWEET: Lazzarini]It came as the UN Relief Works Agency (UNRWA) for Palestine warned one in five children in Gaza City was now malnourished, and cases were increasing daily.
Philippe Lazzarini, who heads the agency, said a colleague had described people in Gaza as "neither dead nor alive, they are walking corpses".
"When child malnutrition surges, coping mechanisms fail, access to food & care disappears, famine silently begins to unfold," he said.
In the last month, 48 people have died from starvation, Gaza's Hamas-run health ministry has said.
More than 100 aid organisations and dozens of governments, including Australia's, this week called for Israel to increase the flow of aid into the Palestinian enclave, as local health authorities warn of growing rates of malnourishment and starvation.
Mr Lazzarini said his organisation's workers were themselves only surviving on one meal a day.
"Most children our teams are seeing are emaciated, weak and at risk of dying," even though UNRWA had the equivalent of 6,000 trucks of aid waiting to enter Gaza, he said.
"Allow humanitarian partners to bring unrestricted [and] uninterrupted humanitarian assistance to Gaza."
The Israeli government has defended its handling of humanitarian aid, accusing Hamas of stealing aid and arguing the distribution of food and medicine in a war zone is complex.
Israel has also previously accused UNRWA of harbouring Hamas fighters, an allegation it denies.
Hamas has denied it is looting aid supplies.
Israeli delegation leaves peace talks in Qatar
An Israeli team preparing to negotiate a potential ceasefire with Hamas left talks on Thursday, local time, leading the militant group to accuse Israel of "stalling" progress.
Amid growing global pressure for an end to the war, the office of Israeli Prime Minister Benjamin Netanyahu announced its team of mediators would return to Israel.
They had been negotiating with representatives for Hamas in Doha, but Mr Netanyahu's office said they were returning for "further consultation" on Hamas's response to ceasefire proposals.
Mr Witkofff said the latest response from Hamas "shows a lack of desire to reach a ceasefire in Gaza".
He said it was "a shame that Hamas has acted in this selfish way" and that the US is "resolute" in seeking an end to the war.
A senior Hamas source told Reuters that there was still a chance of reaching a Gaza ceasefire agreement but it would take a few days because of what he called Israeli stalling.
The source said Hamas' response included requesting a clause that would prevent Israel from resuming the war if an agreement was not reached within the 60-day truce period.
A senior Israeli official was quoted by local media as saying the new text was something Israel could work with.
However, Israel's Channel 12 said a rapid deal was not within reach, with gaps remaining between the two sides, including over where the Israeli military should withdraw to during any truce.
Mounting pressure
Israel is facing international and domestic pressure to find a way to end the war.
Numerous news organisations, including the ABC, have reported that journalists they rely on to report on events inside Gaza are struggling to find food.
The Israeli government has not allowed the ABC to enter Gaza and report from there directly.
The conflict began when Hamas attacked Israel on October 7, 2023, killing more than 1,200 people and taking 251 people hostage.
In response, Israel's campaign against Hamas has killed more than 59,000 people in Gaza, according to local health authorities.
Millions more people have been displaced, and at least 113 people have died of starvation since the conflict began.
One local doctor in Gaza City told the ABC earlier this week that deaths from starvation were beginning to increase.
Further strikes hit Gaza
Meanwhile, Gaza's civil defence agency said Israeli forces had killed at least 40 people since dawn on Thursday, including six waiting for aid.
Israel's military said Hamas militants targeted a food distribution site in the south of the territory on Wednesday.
The militants, though, claimed they had shelled "an enemy command and control site".
Five of those killed on Thursday were in the central Gazan city of Deir al-Balah.
Through 21 months of fighting, both sides have clung to long-held positions, preventing two short-lived truces from being converted into a lasting ceasefire.
In Khan Younis, in the south, Umm al-Abd Nassar urged Hamas to secure a truce after her son was killed in an air strike on a camp for the displaced.
"They need to do something. Enough with this destruction and people dying," she told AFP.
Eight Israeli soldiers injured in car-ramming attack
Meanwhile, eight Israeli soldiers were wounded when a driver deliberately rammed his car into a bus stop on Thursday, local time, according to the Israel Defense Forces (IDF).
Police have described the incident as a "terror attack".
"The soldiers were evacuated to a hospital to receive medical treatment and their families have been notified," the IDF said in a statement.
The army said two soldiers were "moderately injured" and six "lightly injured" in the attack at the Beit Lid junction near Kfar Yona in central Israel.
"The soldiers were evacuated to a hospital to receive medical treatment and their families have been notified," the IDF said.
ABC/wires
