Two years after her escape, Elias is visiting Britain this week with a choir created by young survivors of Islamic State (ISIS) atrocities.

The girls, aged 15 to 22, say the choir provides them with friendship, healing and an escape from the traumatic memories that haunt them.

"I feel very happy with them. It's helped me a lot psychologically," Elias said through an interpreter after performing at a London music conservatory.

The choir has sung at Westminster Abbey and will perform at the Houses of Parliament and in front of Prince Charles, a longtime patron of AMAR, a charity helping with the girls' rehabilitation in Iraq.

The estimated 400,000-strong Yazidi community in Iraq is a Kurdish minority whose faith combines elements of Christianity, Zoroastrianism and Islam.

ISIS, which considers them devil-worshippers, killed and abducted thousands of Yazidis after unleashing a 2014 assault on their Mount Sinjar heartland in what the United Nations says was genocide.

Although the militants were driven out three years ago, most Yazidis still live in camps, too afraid to return.

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Ancient tradition

On a boat ride down the River Thames this week, the girls gathered on the deck to take in the sights and snap selfies.

In their sunglasses and high street fashions, they could have been any group of excited teenagers on their first trip abroad - until they brought out a large tambourine-like daf drum and broke into song.

Music is central to Yazidi religion and culture, but it has never been written down or recorded.

British virtuoso violinist Michael Bochmann has been working with Yazidi musicians and AMAR to record the ancient music.

On Tuesday, Bochmann and the choir handed over the archive to Oxford University's Bodleian Library.

The project also aims to protect Yazidi music by teaching it to hundreds of young people in the camps.

Although traditionally performed by men, nearly half those learning are girls and women, which Bochmann is delighted by.

He said the choir was having a transformative effect.

"It's extraordinary how they've grown in confidence," Bochmann told the Thomson Reuters Foundation.

"The great thing about music is that it makes you live in the here and now. More than any other art form, it can make you happy in the present moment."

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Justice and protection

For their performance, the girls donned long white and lilac dresses tied with orange sashes, and black headdresses adorned with gold.

As they danced with sequined scarves or ululated during a folksong it was hard to imagine the horrors they had endured so recently.

About half the 14 choir members were enslaved. Most did not want to tell their stories, but Elias was keen to speak out.

"I'm not sure whether I'll (ever) recover from what I've experienced," said the teenager who spent three years in captivity.

Elias was sold three times to different men after her abductors took her to Syria.

The second man, a Saudi national, died while she was pregnant. She was sold with her child to a Moroccan who raped her "like a monster", sometimes six times a day.

She became pregnant twice but lost both babies, attributing the first miscarriage partly to torture.

Elias's family secured her release in 2017 for $12,000, but ISIS kept her daughter.

"I suffered a lot. I hope the world community will help us capture the (men) and imprison them," said Elias.

Her sister and two brothers are among thousands of Yazidis who are still missing.

Some choir members were even younger when abducted. One girl was sold five times to ISIS rapists after being kidnapped when she was 11. Another was nine when she was taken as a domestic slave. Her tiny frame suggests how little she was given to eat.

Elias, now 19, said the international community must help rescue remaining captives and ensure the Yazidis are never persecuted again.

It is a message the choir is taking to politicians and religious leaders during their trip to Britain.

While ISIS may have been defeated, the Yazidis say they have not gone away and could resurface.

"The danger is still there. The only thing that can save us is a world commitment to protect us," Elias said.

"What I experienced, the torture and rape, I cannot forget. Of course I'm still afraid."