He claimed the women were being held hostage in Islamic State's stronghold of Mosul, Iraq, which the terror group seized in June last year.
Meanwhile a UN envoy investigating Islamic State's vile sex trade has said 'girls get peddled like barrels of petrol' and one can be bought by six different men.
She also verified a disturbing ISIS document which suggested the extremists sell the Yazidi and Christian women and children they have abducted, with girls aged just one to nine-years-old fetching the most money.
ISIS stormed the Sinjar district in northern Iraq last year and captured hundreds of women belonging to the Yazidi community, who the Islamists view as heretics.
The sex slaves who somehow escaped Islamic State's clutches have told of how they were forced to marry fighters who physically and sexually abused them.
It is not known whether the 19 women executed - supposedly just a few days ago - were Yazidis or not.
They were put to death because they refused to 'participate in the practice of sexual jihad,' a spokesman for the Kurdish Democratic Party in Mosul told Iraqi News.
Said Mimousini also claimed issues around money and the distribution of women have caused a rift within ISIS's ranks.
In October, the terror group released a pamphlet which showed how much it charged for the purchase of its female captives.
Its authenticity was debated until April, when the UN's special envoy for sexual violence in conflict confirmed it was genuine during a trip to Iraq.
Zainab Bangura told Bloomberg: 'The girls get peddled like barrels of petrol... One girl can be sold and bought by five or six different men.
'Sometimes these fighters sell the girls back to their families for thousands of dollars of ransom.'
The shocking document described the women it abducted as 'items' and claimed a decrease in demand of 'women and cattle' affected 'Islamic State revenues as well as the funding of mujahideen in the battlefield'.
It then gives the prices of women and children by age, with one to nine-year-olds costing the most - around £110. The older the women, the lower the price.
The pamphlet - published on October 16 - goes on to say: 'Customers are allowed to purchase only three items with the exception of customers from Turkey, Syria and Gulf countries...
ISIS Executes 19 Girls For Refusing To Have Sex With Fighters As UN Envoy Reveals How Sex Slaves Are 'Peddled Like Barrels Of Petrol'
Posted by Women Against Shariah on Friday, August 7, 2015
From the Daily Mail: