The UN human rights chief Thursday deplored the "grim milestone" of 40,000 Palestinians reported killed in Israel's 10-month assault on Gaza, accusing the country's military of breaking the "rules of war".

United Nations High Commissioner for Human Rights Volker Turk blamed Israel for the soaring death toll in the territory, where it launched a fierce assault in response to unprecedented attacks by Hamas militants in October.

The health ministry in Hamas-run Gaza said on Thursday that the death toll from the conflict had reached at least 40,005 people, with another 92,401 wounded. The ministry does not provide a breakdown of civilian and militant deaths.

"Today marks a grim milestone for the world," Turk said in a statement.

"Most of the dead are women and children. This unimaginable situation is overwhelmingly due to recurring failures by the Israeli Defense Forces to comply with the rules of war," he added.

"The scale of the Israeli military's destruction of homes, hospitals, schools and places of worship is deeply shocking."

He said his office had documented "serious violations" of international humanitarian law by both the Israeli military and Palestinian armed groups, including Hamas.

He reiterated a call for an immediate ceasefire and for the release of Israeli hostages held in Gaza and of Palestinians "arbitrarily detained".

Ceasefire talks resumed in Qatar on Thursday.

Hamas's unprecedented October 7 attack on southern Israel triggered the war and resulted in the deaths of 1,198 people, mostly civilians, according to an AFP tally of Israeli official figures.

Militants also seized 251 people, 111 of whom are still held in Gaza, including 39 the military says are dead.

In response to Turk's statement, Israel's mission in Geneva accused his office of "once again spreading Hamas' propaganda, voluntarily refusing to differentiate between terrorists and civilians".

"For nearly 20 years, Hamas has turned Gaza into a terrorist stronghold. Its brutal strategy is clear: hide behind Palestinian civilians to target Israelis," it said.

"Lives lost on both sides are a victory for Hamas. Today's statement only emboldens Hamas and encourages them to continue their disinformation campaign."