An SAS sniper was able to stop a group of jihadis launching a suicide bomb attack by killing the terrorists with just three bullets in a dramatic shoot-out in an ISIS-held part of Iraq.

The marksman, who joined the SAS a decade ago, potentially saved the lives of hundreds of innocent people by firing three well-aimed shots at the jihadists as they left a bomb factory near Mosul.

The sniper was given the go-ahead after the men were spotted leaving the bomb factory wearing heavy coats in hot weather – a sign they were trying to hide their suicide vests.

Scroll down for video

The SAS marksman potentially saved the lives of hundreds of innocent people by firing three well-aimed shots at the group of jihadists as they left a bomb-making factory near Mosul, an ISIS stronghold in Iraq (file picture)

They were on their way to carry out a terror attack at a nearby town, in which they planned to detonate their suicide vests amongst hundreds of civilians – causing mass deaths.

However, the SAS veteran wiped out all three of the extremists, as well as two 'guards' who were supposedly in place to keep a look-out and protect them from military forces.

The sniper shot the first jihadi in the chest as he walked out of the factory, which caused his suicide vest to detonate, killing him instantly - as well as two ISIS 'guards' who were sat in a nearby car.

The second ISIS militant was wiped out by a shot to the head, while the third was also killed when the sniper's bullet struck his suicide vest and caused it to detonate.

An Army source said the operation, which occurred two weeks ago about 10 kilometres outside of the ISIS stronghold of Mosul, was a 'classic SAS mission'.

The source told the Daily Express: 'The intelligence guys got information that a bomb factory had been set up in a nearby village.

With just three well-aimed shots that single team has probably saved the lives of hundreds of innocent people Army source

'There were too many civilian homes nearby and children were often around so an airstrike was out of the question.

'Instead, the SAS commander in Iraq decided to use a sniper team and the operation was a complete success.

'With just three well-aimed shots that single team has probably saved the lives of hundreds of innocent people.'

The fascinating insight into the sniper's work comes just days after it was revealed how a crack team from the SAS tracked down ISIS executioner Jihadi John and called in the air strike that killed him in Syria.

The top-secret operation to eliminate the masked British extremist – who beheaded UK hostages Alan Henning and David Haines – was thought to have been conducted entirely from the air without any Western troops.

But it was revealed last week that the perilous plan depended on a team of eight men from the Special Forces regiment risking their lives to penetrate deep inside the ISIS stronghold of Raqqa.

ISIS's chief executioner Jihadi John - real name Mohammed Emwazi (pictured above) - was evaporated by a Hellfire missile from a drone after being tracked down by the SAS in the ISIS stronghold of Raqqa last month

The daring mission began on November 11 when two U.S. Chinook helicopters landed at an isolated spot in the Syrian desert.

Avoiding all roads, the team of soldiers drove in desert buggies 35 miles south towards Raqqa and – in the middle of the night - they 'dug in' five miles outside the city, where they remained undetected.

The following evening, while the rest of the team were on lookout, one man assembled four 3ft nano-helicopters with infrared and night-vision cameras in the nose. They were pre-programmed to fly to Jihadi John's hideout – a six-storey building in Raqqa.

The first drone set off towards its target, then entered 'hover and stare' mode, recording the movements of ISIS suspects at a building near the Sharksa mosque.

It beamed footage by satellite back to SAS HQ in Hereford and the U.S. Central Command in Doha, Qatar before a second and subsequently third drone took over.