Israeli warplanes struck parts of the Gaza Strip overnight into Saturday in relentless bombardments, including some of the dwindling slivers of land Palestinians had been told to evacuate to in the territory’s south.

The latest strikes came a day after the US vetoed a UN resolution demanding an immediate humanitarian ceasefire in Gaza, despite it being backed by the vast majority of Security Council members and many other nations. The vote in the 15-member council was 13-1, with the UK abstaining.

“Attacks from air, land and sea are intense, continuous and widespread,” UN Secretary-General Antonio Guterres said before the vote. Gaza residents “are being told to move like human pinballs — ricocheting between ever-smaller slivers of the south, without any of the basics for survival”.

Guterres told the council that Gaza was at “a breaking point” with the humanitarian support system at risk of total collapse and that he feared “the consequences could be devastating for the security of the entire region”.

Gaza’s borders with Israel and Egypt are effectively sealed, leaving Palestinians with no option other than to seek refuge within the territory. The overall Palestinian death toll in Gaza has surpassed 17,400, the majority of them women and children, according to the health ministry in the Hamas-controlled territory, whose counts do not differentiate between civilians and combatants.

Israel holds Hamas responsible for civilian casualties, accusing the militants of using civilians as human shields, and says it’s made considerable efforts with its evacuation orders to get civilians out of harm’s way.

On Saturday, the Israeli military said its forces fought and killed Hamas militants and found weapons inside a school in Shijaiyah, a densely populated neighbourhood of Gaza City.