Health workers are also facing agonizing decisions, like giving up on a seven-year-old boy with extensive burns because bandages are in short supply and he'd have probably died anyway.

These are just some of the horrors witnessed by American doctors and nurses returning from the besieged Palestinian territory, who are now on a mission to spread the word about what they saw and apply pressure on Israel to allow in more life-saving supplies.

"Whether or not a ceasefire happens, we have to get humanitarian aid. And we have to get it in sufficient volumes to meet the demands," Adam Hamawy, a former US army combat surgeon, tells AFP in an interview after a medical mission to Gaza's European Hospital last month.

"You could give all you want, you can donate," says the reconstructive plastic surgeon from New Jersey. "But if these borders don't open up to allow that aid to get in, then it's just useless."

Hamawy has volunteered in war-torn and natural disaster-hit countries for the past 30 years, from the siege of Sarajevo to the Haiti earthquake.

"But the level of civilian casualties that I experienced was beyond anything I'd seen before," says the 54-year-old, who helped save the life of Senator Tammy Duckworth when she lost both of her legs to a rocket-propelled grenade (RPG) attack on the helicopter she was flying in Iraq.

"Most of our patients were children under the age of 14," he stressed. "This has nothing to do with your political views."

Rampant infections

Hamawy and other medics told AFP they are convinced that for now their energy is better spent lobbying the halls of power to stop the war and require Israel to comply with international law by letting in more aid and stop its blockade on necessary aid.

On a hot June afternoon in the capital Washington, Monica Johnston, a 44-year-old ICU nurse from Portland, Oregon said she conveyed specific lists of what was needed in meetings she had held with White House officials and lawmakers on Capitol Hill.

Unlike Hamawy, her journey to Gaza was her very first medical mission.

"I don't watch the news, I don't take part in anything political," she said. But last fall, she received an email from the American Burn Association with an urgent call for help. "Anytime I hear the word 'help,' my ears perk up, my heart starts pumping, and I feel I need to do that."

A 19-member team organized by the Palestinian American Medical Association set off with packed suitcases, bidding farewell to their families.

On the ground, they faced daunting challenges: not enough health workers, as well as a severe scarcity of vital medicines and even basic hygiene supplies, which led to the rampant spread of infections.

Johnston's voice cracks with emotion as she recalls the decision to stop treating a seven-year-old boy's extensive burns, prioritizing resources for patients with a better chance of survival.

"Two days later, he started developing maggots in his wounds, and then the feeling of responsibility that I caused this," she says. He was buried in his bandages because his body was totally infested.

Families wiped out

Whole families often arrived together, explained Ammar Ghanem, a 54-year-old ICU doctor from Michigan. This stemmed from the common practice of extended relatives living in multistory buildings, making them more vulnerable to bombings.

A case in point was a cheerful 12-year-old boy who used to volunteer at the hospital, a source of inspiration for the medics. But for several days, he stopped coming.

When he finally returned, Ghanem learned tragic news: thirty members of the boy's extended family had been killed in a single bombing, and he himself had to help pull their bodies from the rubble.

Initially, the team felt relatively safe, but that changed abruptly after the Rafah crossing was closed after Israel gained control of the Palestinian side of the crossing. This triggered deep anxiety in their Palestinian colleagues, who expressed a sense of deja vu from Israel's past incursion into northern Gaza and the multiple evacuations they'd been through.

Though they were penciled in for a two-week mission, they were left stranded for days until an intervention from the US embassy -- a harrowing time for their partners and children back home.

Now home, they grapple with survivor's guilt, thinking of patients and colleagues left back in Gaza. They also feel grateful for small things, from clean surgical gloves to filling meals.

"What makes me feel better is feeling that I'm making a difference by relaying this message and telling people what I witnessed -- I think that's as important as what we did over there," says Hamawy.

Israel 'deliberately' blocking aid to Gaza

The humanitarian aid allowed into the Gaza Strip is not getting to civilians in need, the United Nations said in late May, urging Israel to fulfil its legal obligations.

"The aid that is getting in is not getting to the people, and that's a major problem," Jens Laerke, spokesman for the UN humanitarian agency OCHA, told a media briefing in Geneva.

He highlighted the responsibility of the Israeli authorities at their Karm Abu Salem crossing, the main entry point for aid into the besieged Palestinian territory since the Rafah crossing between Egypt and Gaza was closed by the Israeli occupation army on May 7.

"We continue to insist that Israeli authorities' obligation under the law to facilitate delivery of aid does not stop at the border," said Laerke.

Anti-poverty charity Oxfam in March accused Israel of intentionally preventing the delivery of aid into Gaza, in violation of international humanitarian law.

The non-governmental organization said in a report that Israel continued to "systematically and deliberately block and undermine any meaningful international humanitarian response" in the Palestinian territory.

It said that Israel was defying an order by the International Court of Justice (ICJ) in January to boost aid in Gaza, and was failing its legal responsibility to protect people in the land it occupies.

"The ICJ order should have shocked Israeli leaders to change course, but since then conditions in Gaza have actually worsened," said Oxfam Middle East and North Africa director Sally Abi Khalil.

"Israeli authorities are not only failing to facilitate the international aid effort but are actively hindering it. We believe that Israel is failing to take all measures within its power to prevent genocide."

The UN, in late February, said Israeli forces are "systematically" blocking access to people in Gaza, complicating the task of delivering aid in what has become a lawless war zone.