An expert SAS sniper took out three ISIS bombers by shooting through a 10inch wall, from a kilometre away with the world's most powerful rifle.

The marksman, considered one of the best in the special forces, fired 30 armour-piercing rounds from his Barrett Light .50 calibre rifle into a two-storey command post in the city of Ramadi in Iraq.

The daring and skillfully executed mission which was called a 'classic SAS operation' saved the lives of around 20 people according to military sources.

The SAS sniper saved the lives of 20 people when he made the shots at the ISIS command post (file picture)

Holding the rank of staff-sergeant, the sniper was part of an elite team of military advisers embedded in the Iraqi army.

After discovering that the bombers were in the building, a number of offensive options were considered including an air strike and a rocket launch.

However, both were deemed too dangerous to civilians as a number of innocent people were being used as human shields around the property.

A source told the Daily Star Sunday: 'The SAS always like to think out of the box.

'The command post was well fortified. They considered an air strike but that would cause too much collateral damage.

'They looked at a rocket attack but there was the possibility that the blast might cause the building to collapse and intelligence suggested there were civilians being held in the lower storey and in buildings close by.

'A staff sergeant in charge of one of the SAS teams working with the Iraqis came up with the idea of shooting through the wall.

'It was a case of 'there's nothing to lose.'

The sniper set himself up in another building around 1,000m away and fired into the command post, leaving one of its walls almost completely destroyed.

When the SAS and Iraqi forces stormed the building later that day they found a scene of gore and chaos.

Fight back: Pictured, Iraqi pro-government forces drive a military vehicle during battles with ISIS in Ramadi

Iraqi forces patrol neighbourhoods in the city of Ramadi as they try to secure the area from ISIS fighters

A source said: 'The armour-piercing rounds had a devastating effect. The bodies of the Islamic State fighters had been absolutely pulverised.

'One had been decapitated and another had been cut in half. It was a real scene of carnage - but the tactic proved incredibly effective.

'The lives of around 20 civilians had been saved. 'The suicide attacks had been stopped and, without any command and control, the Isis fighters had retreated into another part of the city. It was a classic SAS operation.'

Iraqi forces have since claimed to have 'liberated' the strategically important city of Ramadi - which was previously overrun with hundreds of ISIS fighters - with the help of a special coalition strike force.

THE WORLD'S MOST POWERFUL RIFLE: BARRETT LIGHT .50 CALIBRE Power: The Barrett Light .50 calibre rifle, pictured, is used by many armed forces across the world The Barrett Light .50 calibre is a semi-automatic rifle used by many armed forces across the world, including Britain where the Royal Marines and the SAS have been known to benefit from its power and precision. Advertisement

Fed by large magazines containing 10 rounds the rifle has a range of up to 1,800m and can destroy vehicles, light armour, parked aircraft and fixed installations such as radar dishes.

It has also been used as a very effective anti-sniper weapon as its rounds can go through brick walls and other solid defences used for cover. It can also be used to clear mines and other hidden explosives.

News of the mission in Ramadi came after it was revealed another SAS sniper stopped 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, last month.

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.

SPECIAL RELATIONSHIP: HOW BRITAIN HELPED IRAQ TAKE BACK RAMADI The Iraqi army has clawed back control of Ramadi thanks to the help of an elite team based 70 miles outside of the strategically important city. The 30-strong coalition 'strike cell' is led by a Royal Artillery major and it co-ordinates air strikes and rocket artillery bombardments against ISIS targets. Since its operation the team has stopped truck bombings, found a car bomb factory, sought out ISIS fighting positions and found a house that was set with a number of explosive traps. When discussing the successful targeting of a truck bomb in the city, Brigadier James Learmont told the Sunday Times why such missions were so important. He said: 'That's the sort of strike that raises morale amongst Iraqi security forces. Taking those out gives the Iraqi security forces the confidence they need to move.' Advertisement

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.