At least 68 Palestinians were killed following an Israeli air strike that hit a refugee camp in central Gaza, the Hamas-run health ministry has said.
The strike hit the Maghazi refugee camp, east of Deir al Balah.
It comes as the Israeli military said 15 soldiers were killed over the weekend – taking the total number of Israel Defence Force (IDF) personnel to have died in 11 weeks up to 481.
The IDF said it was reviewing the report of an airstrike in Maghazi and was committed to minimising harm to civilians.
Footage of the wounded being transported to hospitals was released by the humanitarian aid organisation, the Palestinian Red Crescent.
Medics said a separate Israeli airstrike in Khan Younis, southern Gaza, killed eight Palestinians.
In the Israeli-occupied West Bank city of Bethlehem, Christmas celebrations were cancelled, in which tradition writes that Jesus was born.
The traditional nativity scene in Manger Square was surrounded by barbed wire and rubble.
Fight on until ‘total victory’
The war has killed more than 20,000 Palestinians and displaced nearly 85% of Gaza’s population, according to the Hamas-run Palestinian health ministry, but Israel is standing firm behind their goal of destroying Hamas.
Israeli Prime Minister Benjamin Netanyahu said in a video statement on Sunday the war was extracting a heavy price but added: “We are doing everything to safeguard the lives of our warriors.”
He said his country’s forces are going deeper into the Gaza Strip and that they will fight on until “total victory” over Hamas and the release of the remaining 129 captives.
But Hamas is still putting up tough resistance, evidenced by the deaths of the Israeli soldiers, four of whom were killed when their vehicle was struck by an anti-tank missile, the Israeli Army Radio said.
The IDF released further details of an operation to dismantle a network of Hamas tunnels, where the bodies of five hostages – Warrant Officer Ziv Dado, Sergeant Ron Sherman, Corporal Nik Beizer, Eden Zacharia, and Elia Toledano – were recovered.
Many Hamas fighters were killed and hundreds of weapons found, the IDF said, in what it said was the group’s northern headquarters in Gaza.
The tunnel network, which included two levels, passed beneath a school and a hospital and was connected to a shaft leading to the residence of the Commander of Hamas’ Northern Brigade, Ahmad Andur, the IDF said.
On Sunday, Islamic Jihad – a smaller group allied to Hamas – said a delegation led by its exiled leader Ziad al Nakhalah was in Egypt.
His arrival followed talks attended by Hamas chief, Ismail Haniyeh, in recent days.
Both groups have said they will not discuss any release of hostages unless Israel ends its war in Gaza, while the Israelis say they are willing to discuss only a temporary pause in fighting.
It comes after the UN fell short of calling for a humanitarian ceasefire on 22 December, instead passing a resolution for increased aid to be transported into Gaza.
The US abstained from the vote, as Israel’s most powerful ally. The resolution sparked criticism from both Israel and Hamas.