GENEVA - Palestinians living in the Gaza Strip are living in "utter, deepening horror", the UN human rights chief said Wednesday, as he called for an urgent ceasefire between Israel and Hamas.

Volker Turk said that in such "apocalyptic" humanitarian circumstances, there was a high risk of atrocity crimes being committed.

"Civilians in Gaza continue to be relentlessly bombarded by Israel and collectively punished -- suffering death, siege, destruction and deprivation of the most essential human needs such as food, water, lifesaving medical supplies and other essentials on a massive scale," he told a press conference.

"Palestinians in Gaza are living in utter, deepening horror."

He said 1.9 million of the 2.2 million people living in the Palestinian enclave had been displaced and were being pushed into "ever-diminishing and extremely overcrowded places in southern Gaza, in unsanitary and unhealthy conditions".

"The catastrophic situation we see unfolding in the Gaza Strip was entirely foreseeable and preventable. My humanitarian colleagues have described the situation as apocalyptic.

"In these circumstances, there is a heightened risk of atrocity crimes," the United Nations high commissioner for human rights said.

"As an immediate step, I call for an urgent cessation of hostilities and the release of all hostages."

Turk said the human rights crisis in the occupied West Bank was also "extremely alarming", as he called for the Israeli authorities to take immediate steps to end "widespread impunity" for violations.

Israel declared war on Hamas after the militant group's October 7 attacks that killed 1,200 people, mostly civilians, according to Israeli authorities, and saw around 240 hostages taken into Gaza.

The latest toll from the Hamas-run government media office said 16,248 people in Gaza, most of them women and children, had been killed.

Israel has vowed to destroy Hamas and free 138 hostages still held after scores were released during a short-lived truce.

"All parties are aware of what is really needed to achieve peace and security for Palestinian and Israeli peoples; violence and vengeances can only result in more hatred and radicalisation," Turk concluded.

"The only way to end the accumulative sufferings is ending the occupation and achieving the two-state solution."