It was a game that three-year-old Reem would only play with her grandfather – the kind of silly, intimate, playful routine that children love to repeat over and over again.

With a mischievous smile, she would tug at his salt-and-pepper beard. Then he would gently pull on her curly pigtails. Whoever could hold on longest was the winner.

“I’ll let go, if you let go,” she says giggling in the video.

“She had such a big heart – she loved people and people loved her back,” Khaled Nabhan, a 53 -year-old gardener from central Gaza, told The Telegraph.

Reem was killed just a month before her fourth birthday in a devastating air strike on the Nuseyrat refugee camp on Nov 21 last year. Her five-year-old brother, Tarek, was killed as well.

They are just two of over 13,000 Gazan children killed during Israel’s six-month-long war with Hamas, according to UNICEF – a figure that dwarfs the total child fatalities from the last four years of conflict worldwide.

The conflict began when Hamas terrorists stormed across the border, killing at least 1,200 civilians including 38 children – some of whom were murdered in their parents’ arms.

Hamas has denied children and civilians access to the underground tunnel network that shelters its leadership, with a spokesman saying early on in the war it was the UN’s responsibility – not its own – to Gazan citizens.

Six months into the war, the toll on young life shows little sign of relenting – and the scars will last a lifetime.

In Mr Nabhan’s last goodbye to his granddaughter, he can be seen holding Reem in his arms, shaking her as if trying to wake her up. Sickly pale and with a scratch on her cheek, the little girl is instantly recognisable from her two buns of black hair.

Her grandfather kisses her and talks to her, even trying to open her eyelids to make sure she is really dead. Eventually he hands her over to the paramedics to be wrapped up in plastic and taken away.

“She was the soul of my soul,” he says in the heart-breaking video, which later went viral.

Mr Nabhan and Reem both shared a birthday on Dec 23, and they were each other’s best friends, he told The Telegraph by phone from Gaza.

He described her as a kind, generous and opinionated girl who loved to get her own way.

With Reem’s father often away working abroad, he had to assume the paternal role.

Although travel outside the enclave of Gaza was either prohibitively expensive or practically impossible, the family liked to get away to the seaside and rent a bungalow for a day or two.

In a video filmed on their shared birthday in December 2021, little Reem laughs and runs across the lawn into the open arms of her grandfather, who is dressed in a traditional ankle-length tunic with a red keffiyeh scarf on his head.

“My darling!” he says to the girl before lifting her up in arms. “We love you so much.” Reem laughs mischievously and tugs at the old man’s beard.

That year, Reem had already experienced her first round of conflict with Israel.

During two weeks of Israeli air strikes and Hezbollah rockets in May, some 260 Palestinians were killed, including 66 children. Reem, just 15 months old at the time, escaped unscathed.

But the war that was sparked by Hamas’s October 7 attack has been far more deadly.

With Gaza’s network of underground tunnels used exclusively by Hamas and no civilian air raid shelters, Mr Nabhan was at home in Nuseyrat with his wife, their daughter Maysa, Reem and Tarek when the Israeli army airstrike hit a building nearby.

“I woke up in fear from the explosion – it was pitch-black, there was dust all around, I had stones on me, windows were smashed,” Mr Nabhan recalled.

“Maysa and the kids were under the rubble… I will never forget the scene. I started screaming for help. I’m still in shock when I think of it.”

Mr Nabhan’s wife and his daughter made it out alive, although Maysa could not speak from the shock and was unaware of her surroundings.

Tarek and Reem both died instantly.

“I called her the soul of my soul – it felt like someone took my life away,” Mr Nabhan said.

When he visited his home a few days later, he picked up a rag doll from the rubble and dust and gave it a kiss – it was Reem’s favourite.

But airstrikes are not the only thing killing children in Gaza – illness and starvation are also rampant.

When Iman Ajaleh, 24, found out that she was pregnant, she was ecstatic.

She had given birth to a girl in 2021 but the baby died 18 days later.

She and her husband Mahmoud, 25, badly wanted children, so they scraped up all their family savings in early 2022 and paid for a round of IVF treatment.

It worked.

By the time Hamas fighters crossed the border into Israel on Oct 7, she was seven months pregnant.

Over the next two months, she and her family fled their home in Gaza City’s densely populated neighbourhood of Shujaiyeh and headed southwards to escape the advancing Israeli army, eventually ending up in the same Nuseyrat camp as Reem and her family.

They arrived shortly after the strike that killed her, just days before Iman was due.

“We were sheltering in a classroom in a school – I remember it was very cold because the windows had been smashed from the blast wave,” Mr Ajaleh, a driver, told The Telegraph by phone from Gaza.

When Iman went into labour, they rushed to the nearest available clinic.

But the scene was a far cry from the calm and organised labour ward they would have been welcomed into before the war.

“Things at the hospital were very tough: you’d see people killed in airstrikes, newborns, kids injured, people with amputated limbs,” Mr Ajaleh said.

The family had been forced to flee from their home with nothing and hadn’t been able to stock up on the usual staples of baby clothes, nappies and toys.

Mr Ajaleh even said he felt guilty for not being properly prepared.

Yet despite the chaos around them, he said the birth of Rajwa was the “most beautiful moment” of his life.

Iman started breastfeeding immediately but it was a struggle.

“She didn’t have much milk because at this point we were only eating canned beef and beans, and maybe cheese – there was nothing fresh at all,” Mr Ajaleh said.

With cramped conditions wherever they went, the family had to improvise: They had no crib for Rajwa so the baby had to sleep on the mattress on the floor with her mum.

Winter was setting in, and living conditions for everyone in Gaza were going from bad to worse.

After a brief spell in the city of Deir Al Balah, the family found itself living in a tent pitched in the street in Rafah, in the south-west corner of Gaza, the only place not affected by heavy fighting.

They held out hope that things would get better soon.

Then, in January, Rajwa started coughing.

When Mr Ajaleh took the 7-week-old baby to a clinic, they were told she had the flu and needed proper nutrition and vitamins, but the hospital had none and the pharmacies were empty.

Three weeks later, she died in hospital. She was 10 weeks old.

“In a normal situation you’d be afraid of bombing and airstrikes but not of the flu,” he said. “But we didn’t have the most basic things for the baby, let alone medication.”

“I still cry every day over her – I have no words to describe the pain I feel.”

Rajwa was buried at a cemetery on the outskirts of Rafah, with her name scribbled on a cement slab placed on top of the grave. A bush was planted in the middle in the absence of fresh flowers.

Mr Ajaleh still regularly flicks through photos of Rajwa on his phone, thinking of all the joy the baby brought to him and Iman.

“The best moment was when Mum would comb her hair – she really liked it and she had a lot of hair for her age,” Mr Ajaleh said.

“This war killed her.”

During Hamas’ brutal attack on Oct 7, their fighters did not spare anyone.

Among their roughly 1,200 victims were 38 children, according to the Israel National Council for Children.

Three of them were under three years old.

Mila Cohen was one of them.

When Ohad Cohen, his wife Sandra and their three children, including 9-month-old Mila, were woken up at their home by air raid sirens in the kibbutz of Be’eri on the morning of Oct 7, they rushed to their safe room.

But they were soon discovered.

Hamas fighters shouted “get out, get out” in English, according to texts Mr Cohen sent to his cousin Shir Druker during the attack.

In his last message, Mr Cohen told his cousin the attackers were trying to break into the safe room, Druker told the JNS news outlet at the family funeral last year.

Mr Cohen was captured and shot dead as he left the safe room, trying to shield his wife and children.

Nine-month-old Mila was shot in her mother’s arms. The Hamas terrorists also shot 73-year-old Yona Cohen, Mr Cohen’s mother.

Sandra and her two other young children survived.

Hamas officials have deflected questions about child victims of the Oct 7 massacre and has never apologised or taken responsibility for the deaths.

They have claimed that women, children and the elderly were kidnapped and killed by Gazan “civilians” who were not part of the original plan.

Some 42 children were abducted to the Gaza Strip.

Almost all of them were released in a ceasefire deal between Israel and Hamas in November.

All but two: Ariel Bibas, 4, and his baby brother Kfir, who turned one this January, are still believed to be in Gaza – the youngest Israeli hostages. Six months into the war, it is unclear if either are still alive – but their extended family are holding out hope.

In one of the most hair-raising videos to emerge from the Oct 7 attack, the terrified mother, Shiri, can be seen holding her kids and hyper-ventilating as several men with automatic rifles kidnap her from her home in Nir Oz.

After trying to resist, Shiri’s husband Yarden was snatched by gunmen and led away. An AP photo from the attack showed him with his head and neck covered in blood.

Yarden has been kept in Gaza separately from his family, according to the hostages who were released.

In February, the IDF released a video made in Gaza on Oct 7, showing Shiri Bibas hustled by gunmen in a backyard somewhere in the city of Khan Younis as she clutched her toddler and infant shortly after their abduction.

Ariel is clearly recognisable in the video thanks to his bright red hair. The gunmen then throw a sheet on Shiri, hiding Ariel and Kfir who appears to be in a baby carrier on her chest.

Hamas claimed early on in the war that Shiri, Ariel and Kfir were all killed in Israeli airstrikes, even putting out a video of their father blaming Prime Minister Benjamin Netanyahu for their deaths.

Mr Bibas appeared extremely distressed and was likely speaking under duress.

Israel does not have any verified reports confirming their deaths. It believes that Shiri and her children were handed over by Hamas to another terrorist group and that is why they were not released last November.

The Bibas’ relatives have not stopped campaigning for their release and Kfir has come to symbolise the plight of the Israeli hostages.

Posters with a photo of the baby – also red-headed – clutching a pink elephant toy and grinning with a toothless smile can be seen plastered on walls across Israeli cities.

Shiri’s cousin Jimmy Miller comes out to protest in Tel Aviv every Saturday in an orange shirt – a nod to his young nephews’ hair colour.

On Kfir’s first birthday, his relatives held a party at their home in Nir Oz, complete with a cake and an arch of orange balloons.

Relatives hope they will be able to see the Bibas boys and their parents soon.

“Ariel and my daughter are best friends. My daughter asks about him all the time, asking why no one can find him?” Ofri Bibas-Levy, a sister of Yarden Bibas, told reporters.

“She’s asking me if he’s dead and I don’t know what to tell her. I don’t have the answers.”

Hamas, Bibas-Levy said, “is the impediment to bringing them home. And we need the help of the international community to pressure Hamas to release them.”