"Israel has perpetrated a concerted policy to destroy Gaza's healthcare system as part of a broader assault on Gaza," the United Nations Independent International Commission of Inquiry said in a statement.
The country is "committing war crimes and the crime against humanity of extermination with relentless and deliberate attacks on medical personnel and facilities", it added.
The three-person commission, established by the UN Human Rights Council in May 2021 to investigate alleged international law violations in Israel and the Palestinian territories, was publishing its second report since October 7.
The report also highlighted abuse of Palestinian detainees in Israel and captives in Gaza, accusing both Israel and Palestinian armed groups of "torture" and sexual and gender-based violence.
Israel has accused the commission of "systematic anti-Israeli discrimination" and flatly rejected the findings of its June report, which also accused Israel of committing crimes against humanity, including "extermination" in Gaza.
'Wanton destruction of healthcare'
"Israel must immediately stop its unprecedented wanton destruction of healthcare facilities in Gaza," commission chair Navi Pillay, a former UN rights chief, said in the statement.
By doing so, "Israel is targeting the right to health itself with significant long-term detrimental effects on the civilian population," she said.
The report found that Israeli security forces had "deliberately killed, detained and tortured medical personnel and targeted medical vehicles" in Gaza and restricted permits to leave the territory for medical treatment.
Such actions constitute numerous war crimes and "the crime against humanity of extermination", the commission said.
Israel's actions had caused "incalculable suffering" among child patients and were "resulting in the destruction of generations of Palestinian children and, potentially, the Palestinian people as a group," it said.
The report highlighted the death of Hind Rajab in January as "one of the most egregious cases".
The young girl called the Palestinian Red Crescent, pleading to be rescued after her family's car came under fire in Gaza City.
Her body was eventually recovered along with six relatives and two Red Crescent rescue workers were sent to find her.
The commission said it determined that the Israeli army's 162nd Division was responsible for the deaths, which constitute war crimes.
'Systematic abuse' in detention
The report examined the treatment of Palestinians held in Israeli military camps and detention facilities.
It found that thousands of detainees, including children, have been subjected to "widespread and systematic abuse, physical and psychological violence, and sexual and gender-based violence".
This amounts "to the war crime and crime against humanity of torture and the war crime of rape and other forms of sexual violence", the investigators said.
Male detainees were subjected to rape and attacks on their sexual organs, they added.
Detainee deaths as a result of abuse or neglect also amount to war crimes, the commission said.
The report found the "institutionalised mistreatment of Palestinian detainees" took place "under direct orders" from National Security Minister Itamar Ben Gvir, fuelled by Israeli government statements "inciting violence and retribution".
Pillay said the "appalling acts of abuse" against detainees required accountability and reparations.
Abuse of captives
Turning to the Israeli and other captives held in Gaza by Palestinian armed groups, the report found that many had been subjected to "physical pain and severe mental suffering", including violence, abuse, sexual violence, humiliation and limited food and water.
"Hamas and other Palestinian armed groups committed the war crimes of torture, inhuman or cruel treatment, and the crimes against humanity of enforced disappearance and other inhumane acts causing great suffering or serious injury," the commission said.
Pillay said all the captives should be released immediately and unconditionally.
Israel's offensive has killed more than 42,000 people in Gaza, mostly women and children, according to figures from the Hamas-run territory's health ministry that the UN has described as reliable.
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