Iman al-Nouri’s youngest son, two-year-old Siraj, woke up crying from hunger on Thursday and asked to get some nutritional supplements.

Siraj’s 14-year-old cousin, Sama, agreed to take him and two of his older brothers – Omar, nine, and Amir, five – to the Altayara health clinic in Deir al-Balah, central Gaza.

“The [medical] point was still closed, so they were sitting on the pavement when suddenly we heard the sound of the strike,” Iman told a local journalist working for the BBC.

“I went to [my husband] and said: ‘Your children, Hatim! They went to the point.'”

Warning: This piece contains graphic descriptions of death and violence

Iman, a 32-year-old mother of five, rushed to the scene after hearing the strike, only to find her sons and niece lying on a donkey cart that was being used to transport casualties to the hospital because there were no ambulances.

Amir and Sama were among the dead, while Omar and Siraj were seriously wounded.

“Omar still had some breath in him. They tried to revive him,” Iman recalled. “Omar needed blood, and it took them an hour to get it. They gave it to him, but it was in vain.”

“Why are they gone? Why? What did they do wrong?” she asked.

“They had dreams just like any other children in the world. If you gave them a small toy, they’d be so happy. They were just kids.”

Iman said Siraj’s head was bleeding and he had lost an eye – an image that she cannot now get out of her head.

“He had fractures in his skull and… according to the doctor, not just bleeding, but [a major haemorrhage] on his brain,” she added. “How long can he stay like this, living on oxygen? Two are already gone. If only he could help me hold on a little longer.”

Tragically, doctors have said they are unable to treat Siraj.

“Since yesterday at 07:00 until now, he’s in the same condition. He’s still breathing, his chest rises and falls, he still has breath in him. Save him!” she pleaded.

A spokesperson for the US-based aid group Project Hope, which runs the Altayara clinic, told the BBC that the strike happened at around 07:15.

Women and children were waiting outside before it opened at 09:00, in order to be first in line for nutrition and other health services, Dr Mithqal Abutaha said.

CCTV footage of the Israeli air strike shows two men walking along a street, just metres away from a group of women and children. Moments later, there is an explosion next to the men and the air is filled with dust and smoke.

In a graphic video showing the aftermath of the attack, many dead and severely wounded children and adults are seen lying on the ground.

“Please get my daughter an ambulance,” one woman calls out as she tends to a young girl. But for many it was too late for help.”

Dr Abutaha said 16 people were killed, including 10 children and three women.

The Israeli military said it targeted a “Hamas terrorist” and that it regretted any harm to what it called “uninvolved individuals”, while adding that the incident was under review.

Project Hope said the strike was “a blatant violation of international humanitarian law, and a stark reminder that no one and no place is safe in Gaza”.

Dr Abutaha said it was “unbearable” when he found out that people were killed “where they [were] seeking their basic humanitarian and human rights”.

He questioned the Israeli military’s statement on the strike, including its expression of regret, saying that it “cannot bring those patients, those beneficiaries back alive”.

He also said that the clinic was a UN-recognised, “deconflicted humanitarian facility”, and that no military actions should have taken place nearby.

Iman said her children used to go to the clinic every two or three days to get nutritional supplements because she and Hatim were not able to give them enough food.

“Their father risks his life just to bring them flour. When he goes to Netzarim [military corridor north of Deir al-Balah], my heart breaks. He goes there to bring food or flour.”

“Does anyone have anything? There’s no food. What else would make a child scream if he didn’t want something?”

Israel imposed a total blockade of aid deliveries to Gaza at the start of March and resumed its military offensive against Hamas two weeks later, collapsing a two-month ceasefire. It said it wanted to put pressure on the Palestinian armed group to release Israeli hostages.

Although the blockade was partially eased in late May, amid warnings of a looming famine from global experts, there are still severe shortages of food, as well as medicine and fuel.

The UN agency for Palestinian refugees (Unrwa) says there are thousands of malnourished children across the territory, with more cases detected every day.

Dr Abutaha said Project Hope had also noticed an alarming rise in cases of malnutrition among adults, which they had not observed before in Gaza.

In addition to allowing in some UN aid lorries, Israel and the US helped set up a new aid distribution system run by the Gaza Humanitarian Foundation (GHF), saying they wanted to prevent Hamas from stealing aid. But since then, there have been almost daily reports of people being killed by Israeli fire while seeking food.

The UN human rights office said on Friday that it had so far recorded 798 such killings, including 615 in the vicinity of the GHF’s sites, which are operated by US private security contractors and located inside military zones in southern and central Gaza. The other 183 killings were recorded near UN and other aid convoys.

The Israeli military said it recognised there had been incidents in which civilians had been harmed and that it was working to minimise “possible friction between the population and the [Israeli] forces as much as possible”.

The GHF accused the UN of using “false and misleading” statistics from Gaza’s Hamas-run health ministry.

Dr Abutaha called on Israel to allow in enough food, medicine and fuel to meet the basic humanitarian needs of everyone in Gaza, so that “everyone could have a dignified life”.

He also expressed concern that people were being given “false hope” that Israel and Hamas could soon agree a new ceasefire deal.

Israeli Prime Minister Benjamin Netanyahu said on Thursday that an agreement on a 60-day truce and the release of 28 hostages could be just days away.

But Palestinian officials said on Friday night that the indirect talks in Qatar were on the brink of collapse because of significant gaps remaining on issues like Israeli troop withdrawals and Hamas’s rejection of an Israeli plan to move all of Gaza’s population into a camp in Rafah.

“Every day they talk about a ceasefire, but where is it?” Iman said.

“They’ve killed us through hunger, through gunfire, through bombs, through air strikes. We’ve died in every possible way.”

“It’s better to go to God than stay with any of them. May God give me patience.”