Hamas has however repeatedly denied that its gunmen assaulted women.
A UN team has concluded there are “reasonable grounds to believe” sexual violence, including rape and gang rape, was committed during the Hamas attacks in Israel on 7 October.
They also said there was “convincing information” that hostages had been subjected to sexual violence.
The trip was led by Pramila Patten, the UN Special Representative on Sexual Violence in Conflict.
Hamas has denied its gunmen sexually assaulted women during the attacks.
“The mission team found that there are reasonable grounds to believe that conflict-related sexual violence occurred in multiple locations during the 7 October attacks,” the UN report said.
These happened in at least three locations – the Nova music festival site and its surroundings, Road 232, and Kibbutz Re’im, it added.
Hamas gunmen infiltrated southern Israel on 7 October – killing about 1,200 people and taking 253 others hostage.
Israel responded by launching a military campaign in Gaza, during which 30,500 people have been killed, according to the Hamas-run health ministry.
Reports of sexual violence carried out by Hamas – which is proscribed as a terrorist organisation by Israel, the UK and others – began to emerge soon after 7 October and have accumulated steadily ever since.
The BBC has also seen and heard evidence of rape, sexual violence and mutilation of women.
In the report, the UN said it had “found clear and convincing information that sexual violence, including rape, sexualized torture, cruel, inhuman and degrading treatment has been committed against hostages”.
It also said it “has reasonable grounds to believe that such violence may be ongoing against those still held in captivity”.
The UN team visited Israel between 29 January and 14 February.
The mission was made up of Ms Patten and nine experts and was not investigative in nature, but designed to gather and verify allegations, the UN said.
It added that 33 meetings were held with Israeli representatives, and more than 5,000 photographic images were examined as well as 50 hours of video footage.
The report said that “despite concerted efforts to encourage” victims to come forward, the team was unable to interview any of them.
Some allegations of rape and sexual violence could not be verified or were “unfounded”, the report explained, including the graphically publicised case of a pregnant woman whose womb was reportedly torn open and her foetus stabbed.
It also said it had not been able to establish a discernible pattern of genital mutilation.
“Israel welcomes the definitive recognition that Hamas committed sexual crimes,” Lior Haiat, a spokesman for the Israeli foreign ministry, said in response to the report’s publication.
He added that Israel was now “calling for the immediate convening of the [UN] Security Council with the aim of designating Hamas as a terrorist organisation and the imposition of international sanctions on it”.
However, Mr Haiat rejected the UN team’s report that it had also received information about sexual violence against Palestinian men and women in detention settings, during house raids and at checkpoints after 7 October.
“That is a derisive and deliberate Palestinian manoeuvre aimed at creating an intolerable equivalence between the horrific crimes that were committed, and continue to be committed, by Hamas and malicious and baseless claims made against Israel and Israelis”.
Israel has rejected similar allegations made previously by a panel of independent UN experts as “despicable and unfounded”.
Mr Haiat also said Israel opposed a recommendation made in the report that the country cooperate with the UN’s international Commission of Inquiry, which is trying to conduct an investigation into potential war crimes on all sides.
He accused the inquiry of being hostile to Israel.
Meanwhile, Israeli Foreign Minister Israel Katz on Monday recalled the country’s ambassador to the UN for “consultations”, accusing the organisation of an “attempt to silence the grave UN report on the mass rapes”.
He criticised UN Secretary General Antonio Guterres for not convening the Security Council to discuss the findings and in order to declare Hamas a terrorist organisation.
UN spokesman Stephane Dujarric said that Mr Guterres “has fully supported” Ms Patten’s work in her visit to Israel.
“In no way, shape or form did the secretary-general do anything to keep the report ‘quiet.’ In fact, the report is being presented publicly today,” Mr Dujarric said.
