GENEVA, Switzerland -- The UN human rights chief on Thursday decried allegations of serious rights violations in the Israel-Hamas war and suggested an international investigation was needed.

Volker Turk said "extremely serious allegations of multiple and profound breaches of international humanitarian law, whoever commits them, demand rigorous investigation and full accountability".

Turk was speaking after a visit last week to the Middle East, where he warned that both sides were committing war crimes in the deadly conflict.

"Where national authorities prove unwilling or unable to carry out such investigations, and where there are contested narratives on particularly significant incidents, international investigation is called for," he said in a briefing to UN member states in Geneva.

It was vital, he told reporters later, for his office to access the Palestinian territories "to ensure full and independent monitoring and documentation and to coordinate the protection work".

He said he had "asked Israel to give me access both to Israel, but also to the occupied Palestinian territory. I have not yet received a response".

Israel has vowed to eradicate Hamas in retaliation for the attacks of October 7, which killed 1,200 people, most of them civilians.

Hamas also took around 240 people hostage, among them elderly people and young children.

Israel's relentless bombardment and ground offensive in Gaza has killed more than 11,500 people, also mainly civilians and including thousands of children, according to the Hamas-run health ministry.

- West Bank warning -

Turk told member states the crisis extended well beyond the Gaza Strip and voiced deep concern about the "intensification of violence and severe discrimination against Palestinians in the occupied West Bank, including East Jerusalem".

"This creates a potentially explosive situation and I want to be clear: we are well beyond the level of early warning," he said.

"I am ringing the loudest possible alarm bell about the occupied West Bank."

He urged an immediate ceasefire and called on all parties to acknowledge the equal value of all human lives.

"It is apparent that on both sides, some view the killing of civilians as either acceptable collateral damage, or a deliberate and useful weapon of war," he said.

He also insisted that "the Israeli occupation must end".

"Israelis' freedom is inextricably bound up with Palestinians' freedom. Palestinians and Israelis are each others' only hope for peace."

- Israel, Palestinians respond -

Israel harshly criticised UN attempts to balance criticism about violations, insisting that international law was "not a suicide pact".

If a state cannot defend itself "or is criticised for doing so in line with international law, inevitably terrorist organisations will become more and more emboldened," Israeli ambassador Meirav Eilon Shahar told the gathering.

"There is no moral equivalence between Israel and Hamas. We will not let Israel, be delegitimised by misrepresentation of reality," she said.

Israel was "not acting out of rage" but rather "out of its obligation to protect its civilians," she added.

Across the room, Palestinian ambassador Ibrahim Khraishi flatly rejected that view.

"You should wake up in this room. This is a massacre, this is genocide," he said, accusing Israel of acting "above the law".

"The problem didn't start on October 7 -- It started 75 years ago," he said.

He received support from a range of countries, including from Jordan's representative who insisted that "Israel must halt its aggression".

US ambassador Michele Taylor meanwhile branded the October 7 Hamas attack as "pure evil", and mourned the Palestinians killed "by the violence resulting from these attacks".