Meanwhile, the Trump administration's Mideast envoy, Steve Witkoff, was set to meet with a senior Israeli official about ceasefire talks, a sign that lower-level negotiations that have dragged on for weeks could be approaching a breakthrough.
The head of the World Health Organisation said Gaza is "witnessing a deadly surge" in malnutrition and related diseases, and that a "large proportion" of its roughly 2 million people are starving, as a result of Israel's response to the October 7, 2023, attack by Hamas
Israel says it allows enough aid into the territory and faults delivery efforts by UN agencies, which in turn say they are hindered by Israeli restrictions and the breakdown of security.
Hamas has said it will only release the remaining 50 hostages it holds, around 20 of them believed to be alive, in exchange for a lasting ceasefire and an Israeli withdrawal. Israel has vowed to recover all the captives and continue the war until Hamas has been defeated or disarmed.
In an open letter, 115 organisations, including major international aid groups such as Doctors Without Borders, Mercy Corps and Save the Children, said they were watching their own colleagues, as well as the Palestinians they serve, "waste away."
The letter blamed Israeli restrictions and "massacres" at aid-distribution points. Witnesses, health officials and the UN human rights office say Israeli forces have repeatedly fired on crowds seeking aid, killing more than 1,000 people. Israel says its forces have only fired warning shots and that the death toll is exaggerated.
The Israeli government's "restrictions, delays, and fragmentation under its total siege have created chaos, starvation, and death," the letter said.
WHO Director Tedros Adhanom Ghebreyesus said rates of acute malnutrition exceed 10 per cent and that among pregnant and breastfeeding women, more than 20 per cent are malnourished, often severely.
The UN health agency's representative in the occupied Palestinian territories, Dr. Rik Peeperkorn, said there were more than 30,000 children under 5 with acute malnutrition in Gaza and that the WHO had reports that at least 21 children under 5 have died so far this year.
The Israeli Foreign Ministry rejected the criticism in the open letter and accused the groups of "echoing Hamas' propaganda." It said it has allowed around 4,500 aid trucks into Gaza since lifting a complete blockade in May, and that more than 700 trucks are waiting to be picked up and distributed by the UN.
That's an average of around 70 trucks a day, the lowest rate of the war and far below the 500 to 600 trucks a day the UN says are needed, and which entered during a six-week ceasefire earlier this year.
White House press secretary Karoline Leavitt said Witkoff was headed to Europe to meet with key leaders from the Middle East to discuss the latest ceasefire proposal and release of hostages.
The evolving deal is expected to include a 60-day ceasefire in which Hamas would release 10 living hostages and the remains of 18 others in phases in exchange for Palestinians imprisoned by Israel. Aid supplies would be ramped up, and the two sides would hold negotiations on a lasting truce.
Israel has continued to carry out waves of daily airstrikes against what it says are militant targets but which often kill women and children. Israel blames civilian deaths on Hamas because the militants operate in densely populated areas.
Hamas-led militants abducted 251 people in the October 7 attack and killed around 1,200 people, mostly civilians.
More than 59,000 Palestinians have been killed during the war, according to Gaza's Health Ministry. Its count doesn't distinguish between militants and civilians, but the ministry says that more than half of the dead are women and children.
