The civil defence agency said a dawn air strike on the home of the al-Ghoula family in Gaza City killed 11 people, seven of them children.
AFP images from the Gaza City area neighbourhood of Shujaiya showed residents combing through smoking rubble. Bodies including those of small children were lined up on the ground, shrouded in white sheets.
Late on Friday Hamas had said indirect negotiations with Israel were to resume in Qatar that same night for a truce and hostage release deal. There has since been no update.
The militant group, whose October 7, 2023 attack on Israel triggered the Gaza war, said talks would "focus on ensuring the agreement leads to a complete cessation of hostilities (and) the withdrawal of occupation forces".
Mediators Qatar, Egypt and the United States have been engaged in months of effort that have failed to end nearly 15 months of war.
A key obstacle to a deal has been Israel's reluctance to agree to a lasting ceasefire.
On Thursday, Prime Minister Benjamin Netanyahu's office said he had authorised Israeli negotiators to continue talks in Doha.
In December, Qatar expressed optimism that "momentum" was returning to the talks following the US election of Donald Trump, who takes office in 16 days.
But Hamas and Israel then accused each other of setting new conditions and obstacles.
On January 1, Israeli Defence Minister Israel Katz warned of even more intense retaliatory strikes if rocket fire continued from Gaza and militants did not release hostages they still hold.
Such rocket launches had become rare but have intensified since late December as Israel presses a three-month offensive in the north of the territory.
As the clock ticks down to the handover of power in Washington, the outgoing administration of President Joe Biden notified Congress of an $8 billion arms sale to Israel, a source familiar with the plan said on Saturday.
"The department has informally notified Congress of an $8 billion proposed sale of munitions to support Israel's long-term security by resupplying stocks of critical munitions and air defence capabilities," the official said.
The United States is Israel's largest military supplier.
'Everything was shaking'
Civil defence spokesman Mahmud Bassal said the Ghoula home in Gaza City "was completely destroyed" by the dawn strike.
"It was a two-storey building and several people are still under the rubble," he said, adding Israeli drones had "also fired on ambulance staff".
Contacted by AFP, the Israeli army did not immediately comment on the strike.
"A huge explosion woke us up. Everything was shaking," said neighbour Ahmed Mussa.
"It was home to children, women. There wasn't anyone wanted or who posed a threat."
Elsewhere, the civil defence agency said an Israeli strike killed five security officers tasked with accompanying aid convoys as they drove through the southern city of Khan Yunis.
Bassal accused Israel of having "deliberately targeted" them to "affect the humanitarian supply chain and increase the suffering" of the population.
The army has not yet responded to the accusation.
United Nations rights experts said on Monday that the north Gaza "siege" appears to be part of an effort "to permanently displace the local population as a precursor to Gaza's annexation".
Rescuers said strikes elsewhere in Gaza killed 10 other people.
AFP images showed Palestine Red Crescent paramedics in Gaza City moving the body of one of their colleagues, his green jacket laid over the blanket that covered his corpse.
The health ministry in Hamas-run Gaza said a total of 136 people had been killed over the previous 48 hours.
The Hamas attack that triggered the Gaza war resulted in the deaths of 1,208 people, mostly civilians, according to an AFP tally based on Israeli official figures.
Israel's retaliatory military campaign has killed at least 45,717 people in Gaza, the majority of them civilians, according to figures from the Gaza health ministry which the United Nations considers reliable.
Militants also seized 251 hostages. A total of 96 remain in Gaza, including 34 the Israeli military says are dead.
The armed wing of Hamas, the Ezzedine al-Qassam Brigades, released a video on Saturday of an Israeli hostage held in Gaza since its October 2023 attack.
In the undated, three-and-half-minute video recording that AFP has not been able to verify, 19-year-old soldier Liri Albag called in Hebrew for the Israeli government to secure her release.
