A teacher who was forced to work in ISIS schools has revealed how staff were told to focus on Koran verses about war and murder - and how a friend was stoned to death after refusing to teach jihad.

The woman, named only as Ayat, said she tried to teach children in her home in eastern Syria after ISIS - also known as ISIL - 'closed the schools and turned them into training centres for fighters'.

But terror chiefs found out about the 27-year-old's scheme after the mother of one pupil 'talked too much', Al Jazeera reported.

In the 'Women of ISIL' documentary by Thomas Dandois, she explained: 'The news spread from one person to another. And ISIL found out a teacher was teaching at home and was not following their instructions.

'They told my husband: "She'd better get training in ISIL's laws and teach children at the mosque like we want. Or else..." It was a threat. I had no other choice.'

Primary school teacher Ayat has described how she tried to instruct children in her home in eastern Syria after ISIS 'closed the schools and turned them into training centres for fighters' (Pictured: the al-Khansaa Brigade)

Ayat, whose last name is not known, underwent training in ISIS laws and the 'approved' curriculum, during which she said she was constantly reminded that she was 'one of them and had to abide by the rules'.

The teacher was then made to take an oath in the presence of the emir's wife in Deir ez-Zur.

In the film, Ayat said she was on her guard 'even at home' and would tremble when she saw a vehicle of religious police pass by.

She added that at times, supervisors would make surprise visits to the mosque to check the teachers were 'behaving the way they instructed us to'.

Once, a group of officials came to the place of worship to monitor her work while she was teaching alongside her close friend, Faten.

The 27-year-old explained how a group of ISIS officials once came to monitor her work while she was teaching alongside her close friend, Faten (stock image)

Her friend, however, had refused to teach children the prescribed curriculum and instead allowed her students to draw and sing children's songs.

This led to a clash between Faten and the officials - and the next day, the teacher was arrested at her home.

'She was accused of adultery. And for this, the punishment was stoning until death,' Ayat said. 'They take the person to a specific place and they implement the punishment. And that is exactly what they did with Faten.'

The teacher also recalled an instance in which ISIS began recruiting women her age for the creation of a new brigade. In 2014, the Al-Khansaa Brigade was founded as an all-women police or religious enforcement unit for the extremist group.

'These women used any means possible to convince other women to enlist and take part in the fighting, she said. 'They flattered them by telling them that they would be like men; that they would have authority, power and control - and of course, money'.

When Ayat was asked to join the brigade, she told those in charge of recruitment that she had health issues so they 'would not suspect me of being against them'.