The United Nations says a group of 36 Yazidis have been rescued in Iraq after three years of "slavery" under the rule of the Islamic State (IS) extremist group.

UN humanitarian coordinator for Iraq Lise Grande said that since April 28, when they were rescued, the women and girls from the group had been receiving lodging, clothing, medical, and psychological aid in Duhok, a Kurdish city north of Mosul.

Thousands of Yazidi women and girls were abducted, tortured, and sexually abused by IS fighters after the militants rounded up Yazidis around the town of Sinjar in northwestern Iraq in 2014.

While some have escaped, as many as 3,500 remain in captivity.

The Yazidi faith has elements of Christianity, Zoroastrianism, and Islam. The IS group considers them "devil worshippers."

Most of the Yazidi population, numbering around half a million, remains displaced in camps inside the autonomous Kurdistan region in northern Iraq.

Based on reporting by Reuters and dpa