Israeli forces blew up more residential buildings in Gaza City on Sunday, killing at least 31 Palestinians and prompting many others to flee, Gazan health authorities said, as Israel's tanks pushed further into the densely populated city.

Nearly two years into the war, Israel describes Gaza City as the last bastion of Hamas and the military has been demolishing housing blocks it says were being used by the militant group since launching its ground assault in the city this month.

A pregnant woman and her two children were among those killed on Sunday, medics said. The Israeli military did not immediately comment on the deaths, issuing a statement saying its forces had killed "numerous" militants.

Relatives sifted through the rubble of one of the apartment buildings that was hit in Gaza City, trying to salvage their belongings.

"The mother, the boy, the girl, and the baby in her womb - we found them all gone," said Mosallam Al-Hadad, the dead woman's father-in-law, saying his son had been seriously injured in the strike.

"(He) was in a critical condition. We took him to the hospital, and his leg was amputated," Hadad told Reuters.

Israel said on Saturday its forces had expanded their operations in the Gaza City area over the past few days, killing 30 militants and locating weapons.

On Sunday, witnesses said Israeli tanks were advancing towards the west through Tel Al-Hawa, a southeastern suburb.

The Israeli military estimates that more than 450,000 people have left the city since the start of September. Hamas disputes this, saying just under 300,000 have left and that about 900,000 people remain.

In southern Israel, air raid sirens sounded when Gaza militants fired two rockets across the border, one of which was intercepted and the other fell in an open field, the military said. No casualties were reported.

WESTERN REBUKE

Israel's Gaza City offensive has drawn rebuke abroad, prompting some of Israel's Western allies to announce they will formally recognise a Palestinian state ahead of the annual leaders' gathering at the U.N. General Assembly this week.

British Prime Minister Keir Starmer was expected, opens new tab to announce Britain's recognition of statehood in a break with long-standing policy despite stiff opposition from Israel and disapproval from the United States, the UK's closest ally.

The offensive has also alarmed families of Israeli hostages still held by Hamas in Gaza. Twenty of those 48 captives are thought to still be alive.

Thousands rallied on Saturday night outside Prime Minister Benjamin Netanyahu's official residence in Jerusalem calling on him to make a deal that will end the war and bring the hostages home.

"I accuse the prime minister of leading us for two years down a dead-end path, toward endless war and abandoning our loved ones. Why?," said Michel Illouz, whose son Guy was kidnapped from a music festival in the Hamas attacks which triggered the war.

The October 7, 2023, attacks killed 1,200 people and 251 others were taken hostage, according to Israeli tallies.

Israel's two-year-long campaign has killed more than 65,000 Palestinians, most of them civilians, according to Gazan health authorities, and has spread famine, demolished most buildings and displaced most of the territory's population - in many cases multiple times.