Eight sleeping children killed in one strike, doctors fighting but failing to save an unborn child — such were the stories recounted by Gaza medics on Thursday as Israel stepped up its air strikes.

Gaza's Hamas-run government said that children made up 1,524 of the 3,785 people killed since Israel launched a relentless barrage on Gaza in retaliation for the October 7 Hamas attacks.

Grief-stricken parents carrying the bodies of children in white shrouds through Gaza streets have become a familiar sight since the war started.

Doctors say they are fighting a losing battle against a lack of medicines, water and fuel to keep hospitals running.

Eight children aged between two and five were among 10 people from the same family killed in an air strike on a house in the city of Khan Yunis, in southern Gaza, early on Wednesday, relatives said.

"The children were asleep when they destroyed the house," their 67-year-old grandfather, Abu Mohammad Wafi al-Bakri, said.

Father escaped 

Diyala, Ayman, Hamada, Zaher, Uday, Jamal, Nabil and Acil all came from one extended family and all slept on the ground floor. It took an hour after the raid to find their bodies, rescuers said.

"None of my children were linked to Palestinian organisations and no men were in the house at the time," said Jihad al-Bakri, father of three of the children.

He had left his home an hour before the missile hit to try to find water.

At Najjar hospital in Rafah, doctors mourned the unborn child of a woman killed by a missile strike early on Thursday.

Arij Marwan al-Banna, seven months pregnant, and her daughters, Sarah and Samya, both aged under 10, were killed on the spot, medical sources told AFP.

Banna had fled to her parents' house from northern Gaza after Israel warned its 1.1 million people to head south.

Doctors operated but could not save her child.

She was posthumously named Fatima and her tiny body bag placed atop that of her mother, doctors said.

The Israeli military said on Thursday it had carried out hundreds of air raids in 24 hours, targeting Hamas military infrastructure.

Terrified Gaza residents have flocked to the Rafah border crossing with Egypt, the only possible escape route from the besieged territory, but it has remained closed.

Scores of people waited forlornly about 100 metres (yards) from the crossing hoping that it would reopen to let aid in and refugees out.

US President Joe Biden announced after visiting Israel on Wednesday that Prime Minister Benjamin Netanyahu had agreed to let some food, water and medicines into Gaza. He said some deliveries could be made on Friday.

Wary inhabitants kept away from the gates fearing that they would again be a target for Israel's relentless strikes after the crossing was hit four times last week.

"I have been waiting for three days with my family in a house 10 minutes away. We are ready with our bags but we just don't know if or when the crossing will open," said Mohammed, a 40-year-old working for an Italian group.

Majed, 43, who works for a German organisation, told AFP: "I came on my own this morning. If the crossing opens, I will get my wife and family — they're ready."

He estimated there were about 400 foreigners, dual nationals and employees of international organisations waiting near Rafah.

The Hamas government media office said it had no details on aid deliveries. It said the crossing's head of operations, Fuad Abu Btihan, had been killed in the Israeli strikes.

Israel intensified its air strikes after Biden flew home and clouds of black smoke again rose over Gaza City.

"It's been tough for three nights, but tonight was the hardest," 60-year-old Umm Mohamed Abu Ziada told AFP.