Islamic State freed more than 200 Yazidis on Wednesday, after taking them captive in Iraq last summer.

They were handed over to Kurdish forces in Himera, north of Baghdad and greeted by family and community leaders. In total, 216 people were released, including two Christians, and all of them were elderly or infirm.

The Associated Press reports that the freed captives cried out to God and wept as they were released. Christian farmer Jar-Allah Frensis, 88, told reporters that he and his wife had been "living in constant fear" since militants abducted them from their house in Sinjar last year. The jihadists also took his son, and the couple don't know where he is now.

Another elderly woman said she had told her son and two young daughters to run away as the militants closed in on her village, but stayed behind herself because she was unwell and did not want to slow them down.

"I had lost hope of seeing my children again, but today it has happened," she said as they embraced her and wept.

It is not known why ISIS released the group, though it is not the first time they have done so. Around 200 Yazidis were released by militants in January, many of them were also elderly and infirm, as well as several children. They had been held captive for five months in Iraq.

A minority ethno-religious group, Yazidis have been systematically persecuted by Islamic State during its attempts to create a caliphate. Their religion is an offshoot of Zoroastrianism, which blends ancient religious traditions with both Christianity and Islam. ISIS insurgents believe them to be "devil-worshippers".

Some of the Yazidis released yesterday said they had been held in the Islamic State stronghold of Tel Afar most of the time, but in the days leading up to their release, they were moved from one town to another in Islamic State's self-proclaimed caliphate.

The Yazidis thought they were being led to their execution, but instead, were piled onto a minibus that drove them to peshmerga positions in batches.

Yazidi activists say many remain in the hands of Islamic State, which has often subjected women to rape or sexual slavery. The United Nations said last month militants may have committed genocide against the minority.

A report based on interviews with more than 100 survivors of attacks between June 2014 and February 2015 urged the UN Security Council to refer the issue to the International Criminal Court.

One witness told investigators that ISIS militants laughed as two teenage girls were raped in the next room. A pregnant woman said an ISIS 'doctor' repeatedly raped her, and sat on her stomach telling her: "this baby should die because it is an infidel; I can make a Muslim baby."

"Clearly international war crimes and crimes against humanity and possibly genocide appear to have been committed during this conflict. The genocide part relates particularly to the Yazidis," Hanny Megally, chief of the Asia, Pacific, Middle East and North Africa branch of the UN Human Rights Office, told reporters.

"No community has been spared in Iraq from ISIL's violence... Essentially what we are seeing is the rich ethnic and religious diversity in Iraq that has been shattered completely," said chief UN investigator Suki Nagra.

Additonal reporting by Reuters