The US government has given Israel a warning that if it does not improve access to humanitarian aid in Gaza in the next 30 days, American military funding to the country may be cut.
The ultimatum comes as aid groups warn that they're seeing some of the worst conditions in the Gaza Strip since the war began last October, especially for children.
The letter, signed by Defence Secretary Lloyd Austin and Secretary of State Antony Blinken, was sent to their Israeli counterparts, Defence Minister Yoav Gallant and Minister of Strategic Affairs Ron Dermer, the State Department confirmed.
White House National Security spokesperson John Kirby said the letter aimed to get more "concrete measures" from Israel to increase humanitarian assistance.
"This particular letter … follows a relatively recent decrease in humanitarian assistance reaching the people of Gaza, which is obviously something we've been very, very concerned about since the beginning of the conflict."
The warning was sent in the same week that the US announced it was providing Israel with one of its most advanced air defence systems to help defend against further Iranian ballistic missile attacks.
Deaths mount every day
Hostilities in Gaza have escalated as the northern part of Gaza spends its 12th day under evacuation orders and intense bombardments that make it difficult to safely move out of danger.
At least 50 Gazans were killed in Israeli military strikes on Tuesday, according to Palestinian health officials.
At least 17 people were killed by Israeli fire in Jabalia, while 10 others were killed in Bani Suhaila in eastern Khan Younis in the south when an Israeli missile struck a house.
UNICEF spokesman James Elder said there are two parallel crises that are "devastating the lives of children in Gaza".
"One, essential aid and commercial goods coming into Gaza are more restricted than we have seen in many, many months. Not a single commercial truck has entered for days," he said.
"Two, attacks on children and places where children should be safe, continue. On average, a school – now a shelter for families – has been struck each and every day of October.
"One year ago families lived in homes with water and power and schools. Today they live in overcrowded and unsanitary tents."
The International Committee of the Red Cross' (ICRC) Adrian Zimmerman said families in north Gaza are facing "unimaginable fear, loss of loved ones, confusion, and exhaustion".
"People must be able to flee safely, without facing further danger," Mr Zimmerman, who is the ICRC's Gaza head of sub-delegation, said in a statement.
"Many, including the sick and disabled, cannot leave, and they remain protected under international humanitarian law – all possible precautions must be taken to ensure they remain unharmed."
America's $26.7b in military aid for Israel
With their close relationship, it's little surprise that the US is the country's biggest backer.
The US has spent at least $US17.9 billion ($26.7 billion) on military aid to Israel since the war in Gaza began, according to a report for Brown University's Costs of War project which was completed before the war with Hezbollah escalated.
Israel is the biggest recipient of US military aid in history, though researchers said the $US17.9 billion figure is incomplete, since the Biden administration has made "efforts to hide the full amounts of aid and types of systems through bureaucratic manoeuvring".
To put that in perspective, last week Israel's finance minister calculated the direct cost of funding the war with Hamas to be 100 billion shekels ($39.7 billion).
US aid has included support for Israel's Iron Dome and David's Sling missile defence systems, munitions and arms sales and hand-me-down equipment.
The Terminal High-Altitude Area Defense (THAAD) battery is on its way to the country, along with 100 US troops to operate it.
The THAAD system consists of six truck-mounted launchers, 48 interceptors, radio and radar equipment. It will be the first deployment of American forces to Israel since the start of the war.
Hospitals in Gaza can't cope
The Gazan health system is buckling under the pressure of treating the injured while hospitals themselves can be in the line of fire.
"Hospitals, already under immense strain, are struggling to meet the rising needs. Humanitarian aid, including medical supplies, must reach those who need it most. Medical facilities must be respected and protected," the ICRC's Mr Zimmerman said.
Mr Elder mentioned the case of Hamid, a six-year-old boy who sustained horrendous burns when the house he was sleeping in was hit by an Israeli missile.
"The hospital doesn't have the burn cream that he needs to change the dressing every single day, such is the sheer level of children with horrendous burns based on attacks and the critical lack of medicines."
The Gaza health ministry said a doctor was killed when he tried to help people wounded by Israeli strikes in Al-Falouja in Jabalia. Several other medics were wounded when their ambulance came under fire in the northern and southern Gaza Strip.
The Israeli military said troops had killed dozens of fighters in the Jabalia area over the past day, including a unit that fired an anti-tank missile at them.
The Israeli military's humanitarian unit, COGAT, said in a statement on Tuesday that the operations in Jabalia were targeting terrorist infrastructure and operatives embedded inside civilian areas. It said it was facilitating humanitarian and in particular medical aid to residents.
Hamas denies it embeds its operatives amongst civilians.
30-day deadline for Israel
National Security spokesperson John Kirby said that a similar request for better access for humanitarian aid was sent to Israel in April that received a "constructive response".
It is unclear what measures the US has asked for or what it would consider an adequate response within 30 days. Nor is it clear how they would cut their military aid if those conditions were not met.
As for the situation in Gaza, Mr Elder said the area is being "utterly deprived" of essentials.
"Countless times I've spoken with mothers of toddlers who simply cannot afford formula, the prices are just so incredibly high," he said.
"That's why we're seeing malnutrition rates at levels in Gaza that we've certainly never seen anything like it in previous years.
"So long as restrictions on aid continue, and so long as there remains a disregard for proportionality and the safety of children, this grim trajectory will continue," Mr Elder said.
On Tuesday, local time, the Palestinian health ministry said Israel's offensive has killed at least 42,344 Palestinians since October 7, 2023, after a Hamas-led terror attack killed 1,200 Israelis and took hundreds hostage. There around 95 hostages still unaccounted-for.
