More than 100 aid organisations and human rights groups warned that "mass starvation" was spreading in Gaza, as the United States said its top envoy was heading to Europe for talks on a possible ceasefire and aid corridor.
Israel is facing mounting international pressure over the catastrophic humanitarian situation in Gaza, where more than two million people are facing severe shortages of food and other essentials after 21 months of conflict.
But it denied blocking supplies, saying that 950 trucks' worth of aid were in Gaza waiting for international agencies to collect and distribute.
On the ground, the Israeli military said it was operating in Gaza City and the north, and had hit dozens of so-called "terror targets" across the besieged Palestinian territory.
Gaza's civil defence agency told AFP that Israeli strikes killed 17 people overnight, including a pregnant woman in Gaza City.
'Wasting away'
The United Nations said on Tuesday that Israeli forces had killed more than 1,000 Palestinians trying to get food since the US- and Israel-backed Gaza Humanitarian Foundation (GHF) started operations in late May –– effectively sidelining the longstanding UN-led system.
A statement with 111 signatories, including Doctors Without Borders (MSF), Save the Children and Oxfam, warned that "our colleagues and those we serve are wasting away".
The groups called for an immediate negotiated ceasefire, the opening of all land crossings and the free flow of aid through UN-led mechanisms.
The United States said its envoy Steve Witkoff will head to Europe this week for talks on Gaza and may then visit the Middle East.
Witkoff comes with "a strong hope that we will come forward with another ceasefire as well as a humanitarian corridor for aid to flow, that both sides have in fact agreed to," State Department spokesperson Tammy Bruce told reporters.
Even after Israel began easing a more than two-month aid blockade in late May, Gaza's population is still suffering extreme scarcities.
Aid agencies, though, said permissions from Israel were still limited and coordination to move trucks to where they are needed –– and safely –– was a major challenge.
'Hope and heartbreak'
The humanitarian organisations said warehouses with tonnes of supplies were sitting untouched just outside the territory, and even inside, as they were blocked from delivering the goods.
"Palestinians are trapped in a cycle of hope and heartbreak, waiting for assistance and ceasefires, only to wake up to worsening conditions," the signatories said.
"It is not just physical torment, but psychological. Survival is dangled like a mirage," they added.
"The humanitarian system cannot run on false promises. Humanitarians cannot operate on shifting timelines or wait for political commitments that fail to deliver access."
The head of Gaza's largest hospital said Tuesday that 21 children had died due to malnutrition and starvation in the Palestinian territory over the previous three days.
Mediators have been shuttling between Israeli and Hamas negotiators in Doha since July 6 in search of an elusive truce, with expectations that Witkoff would join the talks as they entered their final stages.
More than two dozen Western governments called on Monday for an immediate end to the war, saying suffering in Gaza had "reached new depths".
Israel's genocidal campaign in Gaza has killed 59,219 Palestinians, mostly civilians, according to the health ministry in the Hamas-governed territory.
