An Israeli airstrike on Gaza hit the home of a doctor, killing nine of her 10 children while she was on duty at her hospital, according to multiple media sources.

Dr Alaa al-Najjar, a paediatric specialist at al-Tahrir hospital within the Nasser medical complex, was treating victims of ongoing Israeli attacks across the Palestinian territory on Friday when she received the bodies of nine of her children killed by a strike in Khan Younis. The eldest of the children was 12.

Nasser hospital reported that one of Najjar’s children and her husband were injured but survived.

Graeme Groom, a British surgeon working in the hospital, told the BBC he had operated on her surviving 11-year-old boy.

Groom said he had been told the father, who is also a doctor, had “no political and no military connections and doesn’t seem to be prominent on social media”.

Footage shared by the director of the Hamas-run health ministry – and verified by the BBC – shows bodies of children being pulled from the rubble of the building near a petrol station in Khan Younis.

The news was confirmed by the hospital in Khan Younis where Najjar works, according to the BBC. Her husband had just returned home after accompanying her to work when the building was struck by Israeli airstrikes.

“Enough! Have mercy on us! We plead to all countries, the international community, the people, Hamas, and all factions to have mercy on us,’’ Youssef al-Najjar, a relative, told Agence France-Presse. “We are exhausted from the displacement and the hunger, enough!”

Mohammed Saqer, the head of nursing at Nasser hospital in Khan Younis, told the Guardian: “Dr Alaa al-Najjar watched with her own eyes as the charred bodies of her seven children were pulled from beneath the rubble – while two remain missing – all while she was on duty at Nasser medical complex.

“Harrowing details recounted by Ali al-Najjar paint one of the most heartbreaking tragedies to befall a paediatrician who dedicated her life to saving children, only to have her own motherhood stolen in a moment of fire and deafening silence.”

It was later reported that nine children had died.

Groom, who is volunteering at Nasser hospital, attended to al-Najjar’s surviving child, Adam.

“The last patient on my list today was an 11-year-old boy who seemed much younger as we lifted him on to the operating table,” Groom told the Guardian.

“His injuries were bad enough but the background, I think, was worse. His father was very badly injured but nine of his brothers and sisters were killed.”

“It is unimaginable,” said Groom. “The father [al-Najjar’s husband] is a physician here at Nasser hospital. We’ve asked about him and he has no political or military connections … it is a particularly sad day.”

Dr Victoria Rose, who is volunteering alongside Groom, received a video of the aftermath of the attack.

“The video shows all of the children being pulled out of the fire and they are absolutely charcoaled to a crisp. It is so horrific,” she said.

On Saturday, the Israel Defense Forces (IDF) told the Guardian: “Yesterday, an IDF aircraft struck a number of suspects who were identified operating from a structure adjacent to IDF troops in the area of Khan Younis.

“The Khan Younis area is a dangerous war zone. Before beginning operations there, the IDF evacuated civilians from this area for their own safety. The claim regarding harm to uninvolved civilians is under review.”

Thee IDF said it had targeted more than 100 sites across the Gaza Strip over the course of the day, as it intensifies its military offensive despite aid agencies warning that the Palestinian population is plunging deeper into malnutrition and famine.

At least 79 people have been killed in Israeli strikes across Gaza in a 24-hour period, leading up to Saturday evening, the territory’s health minister said, adding that the death toll was expected to rise due to ongoing attacks.

On Friday, 30 people and members of the Dardouna family were killed in airstrikes, including very young children. One of the photos – shared by newly awarded Pulitzer prize-winning journalist Mosab Abu Toha – shows the body of a girl less than a year old being pulled from the rubble, still wearing her pyjamas.

Hamas described the airstrike on the home of Najjar as “a horrific massacre”, adding: “This heinous crime clearly expresses the sadistic nature of the occupation, and the level of the deep-rooted spirit of revenge that drives Netanyahu and his gang of murderers and human monsters.”

Francesca Albanese, the UN’s special rapporteur for the occupied Palestinian territories, said the attack represented a “distinguishable sadistic pattern of the new phase of the genocide”.

Israel may start allowing aid groups operating in Gaza to take charge of non-food assistance as pressure mounts to get more aid into the battered territory, according to a letter obtained by the Associated Press.

The letter says food distribution would be left up to a newly established group, the Gaza Humanitarian Foundation, which is backed by the US and Israel but is not yet up and running. Israel accuses Hamas of siphoning off aid but the United Nations and aid groups deny there is significant diversion.

Israel had blocked food, fuel, medicine and all other supplies from entering Gaza for nearly three months, worsening a humanitarian crisis for 2.3 million Palestinians. Experts have warned of a high risk of famine, and international criticism and outrage over Israel’s offensive has escalated.

The IDF has been approached for comment.