Pope Francis on Thursday was thanked by a delegation of Yazidi representatives for his love and support during their persecution at the hands of Islamic State.

The Pope has consistently called for the minority group's protection, and yesterday met with the Yazidi spiritual leader, Sheikh Kato, their secular leader, Tahsin Said Ali Beg, in addition to several other representatives at the Vatican.

Vatican spokesman Fr Federico Lombardi said one delegate called the Pope "father of the poor" and expressed gratitude for his concern.

"The Holy Father assured the delegates of his spiritual closeness and his support in this time of trial, expressing his hope for a quick reestablishment of justice and the conditions necessary for a free and peaceful life for the Yazidi and all minorities facing discrimination and violence," Lombardi said.

The delegates reportedly highlighted good relations between Christiana and Yazidis "during this time of persecution and suffering". Lombardi also said they informed the pope about "the situation of about 5,000 Yazidi women reduced to slavery" by IS militants.

Human Rights Watch reported in October 2014 that hundreds of Yazidi men, women and children were being held in "makeshift detention facilities" in Iraq and Syria. Many had been forced to convert to Islam, while others had been sexually abused, raped, and girls in their teens taken as wives for jihadists.

"The Islamic State's litany of horrific crimes against the Yazidis in Iraq only keeps growing. We heard shocking stories of forced religious conversions, forced marriage, and even sexual assault and slavery," special adviser at HRW Fred Abrahams said.

He added that some of the victims were children.

A document then obtained by IraqiNews.com in November revealed that Yazidi and Christian women are being sold as slaves for as little as £27.

The list revealed that the price of a slave increases as they get younger; a girl between 10 and 20 years old will sell for about £80, while those between the ages of one and nine are sold for just over £100.

Islamic State also issued harrowing guidelines for how its militants are to treat their female slaves.

Dated October/November 2014, a Q&A leaflet details exactly how IS followers are to buy, sell and abuse "unbelieving" women – thought to mean all those who are not Sunni Muslims.

Disturbingly, the pamphlet instructs that "It is permissible to have intercourse with the female slave who hasn't reached puberty if she is fit for intercourse; however if she is not fit for intercourse, then it is enough to enjoy her without intercourse."

The document also clarifies that disciplinary beatings are permitted, though "beating for the purpose of achieving gratification" and torture are not.

The Yazidis, a minority ethno-religious group in Iraq, have been systematically persecuted by the militant group in recent months. Their religion is an offshoot from Zoroastrianism, which blends ancient religious traditions with both Christianity and Islam. IS insurgents believe them to be "devil-worshippers".

On January 1, the Pope tweeted: