More than 100 people were believed to have been killed on Thursday after Israeli troops opened fire on a crowd trying to secure food aid near Gaza City, with Joe Biden admitting an imminent ceasefire is now unlikely.

Israel has denied responsibility for the deaths but has admitted its troops opened fire after they were threatened.

Gazan Kamel Abu Nahel said he and others went to the distribution spot in the middle of the night to make sure they got food.

“We’ve been eating animal feed for two months,” he told AFP from Al-Shifa Hospital, where he was being treated for a gunshot wound.

He said Israeli troops opened fire on the crowd, causing people to disperse and seek shelter. When the shooting stopped, some people tried to return to the trucks for food but soldiers opened fire again.

He added that he was shot in the leg and fell over and then a truck ran over his leg as it sped off.

Another witness, Alaa Abu Daiya, said Israeli troops were shooting and a tank fired a shell.

One video shared on social media, which Reuters was able to verify as being at the roundabout, showed trucks loaded with many dead bodies, as well as wounded people.

According to Fares Fana, the head of the ambulance service at Kamal Adwan Hospital, there were not enough ambulances to collect the dead and wounded. 

Some people were transported in donkey- and horse-pulled carts and medical teams said they were unable to cope with the volume and severity of the injuries, with dozens of wounded taken to the al-Shifa hospital, which is only partially operational after being the target of Israeli raids.

The Hamas-run health authority said more than 100 Palestinians had been killed but Israel challenged the death toll and said many of the victims had been run over by aid trucks.

An Israeli military official said two separate incidents had occurred as the convoy of trucks passed into northern Gaza from the south along the main coastal road.

In the first incident, he said, aid trucks were surrounded by hundreds of people and in the confusion, dozens were injured or killed, by being trampled or run over by the trucks.

As the trucks left, he said, a second incident occurred in which some of the people who rushed the convoy approached Israeli forces including a tank, which then opened fire.

“The soldiers fired warning shots in the air and then fired towards those who posed a threat and did not move away,” he told a news briefing. “From our perspective, this is what we understand. We’re continuing to review the circumstances.”

Mr Biden said that the United States was checking “competing versions” and had discussed the “tragic and alarming incident” with the leaders of Egypt and Qatar.

He told reporters a ceasefire was unlikely to be in place by Monday as he previously suggested, but added: “Hope springs eternal.”

When asked whether the incident would complicate negotiations he replied: “I know it will.”

The deaths meant the Gaza health ministry’s official fatalities toll surpassed 30,000 on Thursday, including 25,000 Palestinian women and children.

Aid supply deliveries into Gaza have become more difficult as the Israel-Hamas war nears its sixth month. In some instances, supplies have been air-dropped in.

“The clock is ticking fast towards severe hunger, starvation and in some cases famine,” said Juliette Touma, director of communications at UNRWA, the main UN aid agency for Gaza.

She added that there had been a drop of about 50 per cent in the average daily number of trucks entering the territory.

UN and other relief agencies have complained that Israel has restricted aid deliveries, which Israel denies.

As a mass humanitarian crisis unfolds, Palestinians have grown increasingly desperate as they try to find ways to survive, with scenes of looting of aid convoys becoming increasingly common.

Umm Hamdan Abu Sultan, a displaced woman who had been waiting for aid, said: “Our children are dying of hunger, we go to get a bag of flour to feed our children and they fire at them.”

The office of Mahmoud Abbas, the Palestinian president, condemned the “ugly massacre conducted by the Israeli occupation army this morning against the people who waited for the aid trucks”.

Hamas has warned that this incident could lead to a breakdown in talks aimed at securing a truce and release of remaining Israeli hostages. If that happens, the group said it would hold Israel responsible for failing to agree a deal.

“The negotiations conducted by the movements’ leadership are not an open process at the expense of the blood of our people,” the group said.

Itamar Ben-Gvir, Israel’s Right-wing national security minister, said the incident showed aid deliveries should be stopped completely as they endangered IDF soldiers.

The UN Security Council is expected to hold an emergency closed-door meeting on Thursday to discuss the events.