GEOFF BENNETT: A United Nations commission is investigating potential war crimes on both sides of the Israel-Hamas war.

But the U.N. agency dedicated to gender equality has been sharply criticized for waiting until this month to express alarm over sexual violence that appears to have been perpetrated during the October 7 Hamas attacks.

Special correspondent Leila Molana-Allen reports on the realities of that day, which are becoming increasingly clear.

And a warning: The accounts are vivid and disturbing.

LEILA MOLANA-ALLEN: Raped repeatedly, mutilated, murdered.

At least 300 women were killed by Hamas terrorists on October 7.

But Israeli activists say the brutal sexual violence they endured has been ignored.

MORAN ZER KATZENSTEIN, Women's Rights Activist: It's too little, too late.

LEILA MOLANA-ALLEN: Moran Zer Katzenstein led protests outside the U.N. this week.

MORAN ZER KATZENSTEIN: Rape is rape.

Rape is not resistance.

We're talking about women's bodies.

And it's not political.

LEILA MOLANA-ALLEN: After dancing through the night, they faced death at dawn.

The bodies of dozens of young women were found at the site of the Nova Music Festival in Southern Israel.

Many, say eyewitnesses, bore the scars of sexual atrocities.

One video shows a young woman burned alive, her legs spread apart.

Combat medic Daniel Elbo Arama and his team rushed to the scene to help as they began to realize what was happening.

Hiding near the site, a young woman begged the soldiers for help.

DANIEL ELBO ARAMA, Combat Medic, Israeli Defense Forces: She was wearing only her bra.

It was cut, not fully there, and only underwear with a lot of blood.

I got to her inside an ambulance and I told her: "Hi, ma'am.

I'm so sorry, but I'm the only one that can treat you.

We don't have females here."

And she held my hands and said: "Do whatever you need.

I want to live."

LEILA MOLANA-ALLEN: Daniel has worked in emergency response for 20 years, much of it in conflict situations.

But what he saw that day will never leave him.

DANIEL ELBO ARAMA: She told me that she was raped by four terrorists.

And she was bleeding so much that they had to give her plasma.

Those medications are usually given to a person that was shot.

She got to a hospital, and she had to undergo a surgery for a few hours just to fix everything that happened to her in the inside of your body.

LEILA MOLANA-ALLEN: Israeli officials say they have collected more than 1,000 testimonies of sexual atrocities, including gang rape and the mutilation of women's bodies, both before and after they were murdered.

Hamas denies the claims.

The task of collecting the bodies and physical evidence fell in part to volunteers like Nachman Dickstein, who gather Jewish remains for burial.

NACHMAN DICKSTEIN, Volunteer: The smell from the dead, smell of the burnt people, like it's something that stay with us.

LEILA MOLANA-ALLEN: The condition of the desecrated female bodies he found in Kibbutz Be'eri stills haunts him.

NACHMAN DICKSTEIN: One lady, she was naked in the bed, tied the hands.

A second one also was tied in the hands, but she was without her head.

LEILA MOLANA-ALLEN: At a hastily erected temporary morgue on a military base outside Tel Aviv, forensics teams have spent the past two months piecing together and attempting to identify shattered and burned human remains.

Ruth Halperin-Kaddari has spent a lifetime working to stop violence against women.

I went to that morgue, that temporary morgue.

There were so many victims, so many bodies, so many pieces of bodies, that trying to collect sexual evidence has been incredibly difficult.

The other challenge here, there's very little in the way of firsthand testimony.

What are the challenge is there in terms of gathering evidence and moving forward to any form of prosecution or justice?

RUTH HALPERIN-KADDARI, Bar-Ilan University: It's actually unthinkable that by murdering, thus silencing forever the victims, their seeking justice for them would also be stopped in that way.

We have evidence of bodies that all exhibit the same pattern of mutilation and signs of sexual assault.

And we have numerous footage and photographs and testimonies from first responders.

LEILA MOLANA-ALLEN: For Halperin-Kaddari, the U.N. and other international organizations have wholly failed in their response.

RUTH HALPERIN-KADDARI: By keeping silent so long, the message that was sent here to the whole world is a very, very concerning one.

It's a message that, for some people, these kinds of acts of crimes, of cruelty could actually be viewed as a legitimate resistance, and perhaps, for others, this conduct could go unaccounted for.

LEILA MOLANA-ALLEN: As the eyes of the world focus on the mounting death count in Gaza, Moran says she and other Israeli women feel betrayed, their suffering sidelined.

Now she hopes their voices will finally be heard.

MORAN ZER KATZENSTEIN: The most important thing is that women that -- everywhere need to understand Hamas and the Palestinian are not the same thing.

And Hamas raped, tortured, kidnaped women.

And if you are with women, you need to speak up for women.

LEILA MOLANA-ALLEN: For the "PBS NewsHour," I'm Leila Molana-Allen.