The teenager, known only as Omar, was serving with more moderate opposition forces trying to overthrow Syrian President Bashar al-Assad's regime when he was captured by the Islamic State.

He says the extremist group strung him up and tortured him for a month and a half in a bid to get him to join their growing ranks of children. When he refused, he was dealt a shocking punishment.

In an interview with Channel 4 from his new home in a Turkish border town, Omar describes how militants gathered a crowd in the middle of a street, before tying down his right hand and left leg.

Speaking in Arabic, he tells reporter Evan Williams: 'They put my hand on a wooden block and cut if off with a butcher's knife. Then they cut off my foot and put them both in front of me for me to see.'

The brave teenager, who was bleeding heavily and in unimaginable pain, was forced to look up at his own severed extremities as the crowd of men, women, children and terrorists watched.

He shows Williams photos of his hand and foot being hacked off with the enormous blade - and an image of the militant who carried out the amputations, a massive man called 'The Bulldozer'.

He describes how 'The Bulldozer' and fellow militants sought out other teenagers and children in the area ahead of the horrifying public display - as a warning to them not to resist the Islamic State.

'They brought teenagers and children and told them, "this man is an infidel so we will cut off his hand and foot",' says Omar as he rests his right stump - wrapped in a large bandage - on his lap.

Omar's amputations took place just three weeks before the Channel 4 interview.

Heartbreakingly, he now says he has 'given up on life'. 

And Omar is far from the only teenager or child to have been ordered to join ISIS.

The terror group is increasingly recruiting children as young as eight to join its ranks. Once these youngsters reach 16, they are expected to start fighting - either as soldiers or suicide bombers.

A female 'teacher' who trained ISIS's young female recruits before recently fleeing to Turkey tells Williams that the group is indoctrinating children through a series of intensive lessons and exercises.

The 'cubs of the Caliphate' undergo daily classes on stripping, reassembling and shooting guns, and participate in violent physical activities that see adult militants kicking and punching them.

The youngsters are taught to 'listen and obey' - even if that means they die in the process.

They are brainwashed into believing ISIS's ideology - and some have even been captured on video carrying out beheadings and other executions in Syria and Iraq on behalf of the extremist group.

The unidentified teacher reveals that ISIS's future plans are to 'attack and destroy many countries'.

Undoubtedly, young soldiers will be a part of these plans, Channel 4 reports.

'The thing ISIS depends on most is children', the teacher says.

The new short film comes just a month after a video was apparently released by ISIS showing a baby-faced boy, no older than three years old, beheading a teddy bear with a sharp knife.

Looking into the camera, the infant holds the bear in his left hand, and the knife in his right, and smiles. He then starts to use the deadly weapon to hack the head off of his cuddly toy.

Seconds later, the boy lifts his knife triumphantly into the air, while a man behind the camera shouts 'takfir!' - a derogatory word used to describe non-believers.

The footage - believed to have been released by ISIS but its provenance is unconfirmed - sparked outrage online, with one Syrian man deeming it a perfect symbolisation of a destroyed childhood'.

Julie Lenarz of the Human Security Centre think-tank called it 'child abuse of the most wicked sort'.

Others suggested the boy was being 'brainwashed' into carrying out beheadings when he grows up. 

ISIS now has control over large swathes of Syria and Iraq. 

It is continuing to gain territory in the two countries despite air strikes against the group.

(dailymail.co.uk)