The 23-year-old Yazidi woman, called for justice for the victims of the jihadist group and argued that the 2014 attack on the Yazidis should be recognised as a genocide.
Murad was taken from her home village of Kocho near Iraq’s northern town of Sinjar in August 2014 and brought to IS-controlled Mosul, where she was gang-raped, and bought and sold many times.
“I was used in the way that they wanted to use me. I was not alone,” Murad said during a ceremony held at UN headquarters.
“Perhaps I was the lucky one. As time passed, I found a way to escape where thousands others could not. They are still captive.”
Her voice trembling, Murad called for the release of some 3,200 Yazidi women and girls still being held as sex slaves by IS fighters and for the captors to face justice.
“My real fear is that once ISIS is defeated, ISIS militants, ISIS terrorists will just shave off their beards and walk the streets of the cities as if nothing has happened,” she said.
“We cannot let this happen.”
Murad said her hope was that one day, Yazidi victims will be able to look “our abusers in the eye before a court in The Hague and tell the world what they have done to us, so that our community can heal.”
As a goodwill ambassador, Murad will focus on raising awareness of the plight of victims of trafficking of persons, especially refugees, women and girls.
She is represented by international lawyer Amal Clooney, who said the Islamic State group must be held accountable for grave crimes.
“We know that what we have before us is genocide, and we know that it is still ongoing,” said Clooney.
“I am ashamed as a human being that we ignore their cries for help,” said Clooney, drawing applause.
As world leaders converge on the United Nations next week for the annual General Assembly debate, Iraq and Britain will on Monday launch a campaign to push for accountability for crimes committed by IS.
Murad and Clooney are due to attend that event along with Britain’s Foreign Secretary Boris Johnson.