One of the worst single tragedies to occur during Israel’s war with Hamas took place Thursday, when scores of Palestinians were killed trying to access food aid in Gaza City.

At least 104 people were killed, and at least 760 were injured, in an incident where Israel Defense Forces (IDF) troops used live fire as hungry and desperate Palestinian civilians were gathering around food aid trucks, according to the Palestinian Ministry of Health in Gaza. CNN is unable to independently confirm these numbers.

The incident took place amid a backdrop of vast hunger and dire poverty in the besieged enclave, where food aid has been so rare as to frequently elicit panic when it arrives.

But there are competing narratives surrounding the devastation that have been put forward by Israel and by eyewitnesses on the ground.

Here’s what we know.

What happened?

The deaths occurred amid scenes of chaos on Haroun Al Rasheed Street in western Gaza City, where crowds of hungry Palestinians had gathered for food aid.

A convoy of at least 18 food trucks arrived at around 4.30 a.m. on Thursday morning, sent by countries in the region including Qatar, Saudi Arabia and the United Arab Emirates, according to eyewitnesses.

Civilians swarmed around the newly arrived aid trucks in the hope of getting food, and Israeli forces soon started shooting, witnesses said.

The aid trucks tried to escape the area, accidentally ramming others and causing further deaths and injuries, the eyewitnesses added to CNN. Ambulances struggled to reach those in need because rubble was blocking the way, one of those witnesses, Ahmad Abu Al Foul told CNN.

The majority of the casualties occurred as a result of people being rammed by aid trucks trying to escape Israeli fire, according to a local journalist in Gaza, Khader Al Za’anoun.

Al Za’anoun, who was at the scene and witnessed the incident, said that while there were large crowds waiting for food to be distributed from aid trucks, the chaos and confusion that led to people being hit by the trucks only started once Israeli soldiers opened fire.

“Most of the people that were killed were rammed by the aid trucks during the chaos and while trying to escape the Israeli gunfire,” Al Za’anoun said.

What is Israel saying?

Israel offered an evolving account of the incident as the day progressed.

In its first comments, the IDF said the incident began when Palestinians attempted to loot the trucks. “Early this morning, during the entry of humanitarian aid trucks into the northern Gaza Strip, Gazan residents surrounded the trucks, and looted the supplies being delivered. During the incident, dozens of Gazans were injured as a result of pushing and trampling,” the IDF told CNN.

Later on Thursday, an Israeli military spokesperson claimed in a briefing that there were two separate incidents involving aid trucks in Gaza Thursday.

First, he said trucks entered northern Gaza and were rushed by crowds, with trucks running over people. Subsequently, he said, a group of Palestinians approached Israeli forces, who then opened fire on the Palestinians.

“The truckloads went into the north, then there was the stampede, and then afterwards, there was the event against our forces. That’s how things transpired this morning,” the spokesman said.

That timeline directly contradicts the eyewitness accounts, which suggested that the Israeli military opened fire on people near the trucks, causing drivers to pull away in panic.

IDF spokesperson Daniel Hargari said at a press conference Thursday there was no strike on the aid convoy. “I want to repeat that. No IDF strike was conducted towards the aid convoy. On the contrary, the IDF was there conducting a humanitarian operation,” he said.

What is the humanitarian situation in Gaza?

More than a half a million people in Gaza are on the brink of famine, United Nations agencies warned on Tuesday, as the war in the enclave stretches towards the five-month mark.

The UN Office for the Coordination of Humanitarian Affairs said at least 576,000 people across Gaza are “facing catastrophic levels of deprivation and starvation.” Meanwhile, the UN World Food Programme (WFP) warned “of a real prospect of famine by May, with 500,000 people at risk if the threat is allowed to materialize.”

“Today, food aid is required by almost the entire population of 2.2 million people. Gaza is seeing the worst level of child malnutrition anywhere in the world,” Carl Skau, WFP Deputy Executive Director, told the Security Council during its Tuesday session. “One child in every six under the age of 2 is acutely malnourished.”

Aid has been so sparse that, when available, it has often prompted panic. Jan Egeland, the Secretary-General of the Norwegian Refugee Council, warned of chaotic scenes around aid trucks in Gaza, during an interview with CNN’s Christiane Amanpour earlier this week.

“The chaos, yes, around the aid line is becoming worse and worse because there’s so little aid coming in,” he said.

“Today, I’m pretty shaken actually from what I saw,” he went on. “The minute we crossed the border … you see the aid trucks going full speed down the road, being chased by gangs of youth who jumped the trucks and before our eyes, loot mattresses, blankets, food, et cetera, to the desperate people outside who want to get some aid.”

How have the US and UN reacted?

The US State Department expressed condolences for those killed and injured and said the US was pressing Israel for answers.

“Far too many innocent Palestinians have been killed over the course of this conflict, not just today, but over the past nearly five months,” said State Department Spokesperson Matthew Miller at a press briefing.

“We have been in touch with the Israeli government since early this morning and understand that an investigation is underway,” he said.

Miller said the US is aware of “conflicting reports” about what happened and would only say the US knows that a commercial convoy not associated with the UN was delivering the aid.

“If there’s anything that the aerial footage of today’s incident makes clear, it is just how desperate the situation on the ground is,” said Miller, calling for Israel to “allow the entry of more assistance into Gaza, through as many points of access as possible, and to enable safe and secure distribution of that aid throughout Gaza.”

The UN has condemned the incident and said it must be investigated. UN Secretary General António Guterres said he was “appalled” by the growing death toll in Gaza and reiterated calls for an immediate humanitarian ceasefire and unconditional release of all Israeli hostages in Gaza.

His spokesman Stéphane Dujarric said in a statement: “The desperate civilians in Gaza need urgent help, including those in the besieged north where the United Nations has not been able to deliver aid in more than a week,”

Saudi Arabia also condemned the incident, calling on the international community “to take a firm stance by obliging Israel to respect international humanitarian law.”

What this means for the war

Thursday’s tragedy represented one of the deadliest single incidents in Gaza since Israel’s war against Hamas began.

And it came at a critical time for the conflict, with negotiations between Israel and Hamas on a deal to pause fighting and allow humanitarian aid into Gaza reaching a potentially pivotal moment.

Hamas senior member Izzat Al-Risheq warned that the killing of people collecting aid from trucks in Gaza could lead to the failure of ongoing talks.

“Negotiations are not an open process,” he said in a statement published by the Hamas on Telegram.

“We will not allow for the pathway of the negotiations…[to become] a cover for the enemy’s continued crimes against our people in the Gaza Strip,” Al-Risheq said.

At the State Department briefing, Miller also said the incident indicated how necessary it was to reach “a potential temporary ceasefire as part of a hostage deal” to allow more aid in.

“We continue to work day and night to achieve that outcome, including through calls the president held this morning with President Al Sisi of Egypt and the Emir of Qatar Sheikh Tamim, as well as one Secretary Blinken held earlier today with Qatari Prime Minister Al Thani,” Miller said.

“Every leader on those calls agreed that this terrible event underscores the urgency in bringing the hostage talks to a close.”

President Joe Biden said Monday during an appearance at an ice cream shop in New York City that he hoped there would be a ceasefire in the Israel-Hamas conflict by “next Monday,” though officials from Israel, Hamas and Qatar – which is helping mediate negotiations – distanced themselves from that timeline.

Biden said Thursday “there are two competing versions of what happened” that his administration is looking into. When asked by CNN’s Arlette Saenz at the White House on Thursday if he worried the deaths would complicate negotiations, Biden responded: “Oh, I know it will.” But he still expressed optimism that a deal on the hostages and a potential ceasefire could be reached soon.