A Palestinian rescuer locates a person trapped under the rubble of a collapsed building following the Israeli bombardment of Khan Yunis in the southern Gaza Strip on Saturday. AFP

Israel resisted US calls for a pause in fighting and pressed its siege of Gaza City on Saturday, after deadly strikes hit an ambulance convoy and a school-turned-refugee shelter.

As Israeli Prime Minister Benjamin Netanyahu rebuffed pressure from visiting US Secretary of State Antony Blinken to enact a temporary humanitarian truce, the nearly month-old war in Gaza raged unabated.

Israeli ground forces have encircled Gaza's largest city, trying to rout Hamas in retaliation for October 7 raids that killed an estimated 1,400 people inside Israel, most of them civilians.

At the Osama Bin Zaid Boys School north of Gaza City, the media saw the aftermath of what Hamas authorities said was Israeli tank shelling that killed 20 people.

Ambulance teams rushed into the debris-littered building to aid the injured and remove the dead.

Stunned onlookers wept and wandered the scene with hands clasped above the head in horror and disbelief.

A Palestinian rescuer locates a person trapped under the rubble of a collapsed building in Gaza. AFP

A long row of washing still hung from windows on the building's first storey, evidence that the school had become a temporary home for some of the hundreds of thousands displaced by the war.

Israel's military describes Gaza City as "the centre of the Hamas terror organisation" and says it is targeting Hamas operatives, weapons stores, tunnel complexes, drone launching posts and command centres there.

Spokesman Richard Hecht said forces were engaged in "very intense, close quarters combat" with Hamas fighters.

But with strikes and ground fighting taking place in densely populated urban areas, many civilians have died.

Hamas-run health authorities claim more than 9,200 Gazans, mostly women and children, have been killed.

Palestinian rescuers attempt to put out a fire as they stand on the rubble of a collapsed building in Gaza. AFP

Speaking in Tel Aviv, Blinken accused Hamas of "cynically and monstrously" using civilians as human shields, and of deliberately locating military assets "beneath residential buildings, schools, mosques, hospitals."

A key focus of his trip was to convince Israel to enact "humanitarian pauses", which the United States believes could help secure the release of roughly 240 hostages thought to be in Hamas captivity, and to allow aid to be distributed to Gaza's beleaguered population.

Netanyahu, who has made a political career out of hawkish security policies, warned that there could be no "temporary truce" in Gaza until Hamas releases the hostages.

Agence France-Presse