Horrific moment Islamist terrorist shows 'enemy's' decapitated head to baying crowd... unaware he has just killed fellow Syrian rebel

Islamic S tate of Iraq and al-Sham severed the head of a fighter in Syr ia

Believed he was a pro-Assad soldier but turned out to be a fellow rebel

Group 'misunderstood' comments he made about Shia founding fathers

In a sickening video posted on YouTube, soldiers from the Syrian-based group Islamic State of Iraq and al-Sham (ISIS) were seen holding up the decapitated head of a soldier they believed was a supporter of President Bashar al-Assad.

But, after the footage was made public, the victim was recognised by an extremist as a fellow rebel fighter who had been wounded during a battle.



The militants have now asked for forgiveness.



Sickening: Soldiers then held the severed head up in front of a crowd in Aleppo

Error: Mohammed Fares, left, who was mistakenly decapitated by Islamic State of Iraq and al-Sham militants

After an investigation the soldier was identified as Mohammed Fares, a commander of Ahrar al-Sham, a group who fight alongside the ISIS .



The Syrian Observatory of Human Rights said ISIS fighters misunderstood comments Mr Fares made about the founding fathers of Shia Islam, Imams Ali and Hussein, according to The Daily Telegraph.



It is thought Mr Fares was injured while fighting pro-Assad forces for the control of military site Base 80 near Aleppo, before he was mistakenly executed.

The militant group tried to explain their error by referring to a story in which the prophet Mohammed said Allah would forgive a man who killed a believer by mistake.



An ISIS spokesman, Oma al-Qahtani, confirmed Mr fares had been injured in fighting and had been captured by soldiers who believed he was fighting against them.

He has now said an investigation into the death would be carried out by the appropriate authorities.



The huge mistake has highlighted chaos within the rebel ranks in Syria, which Assad has taken advantage of in recent weeks during a push by his forces south-east of Aleppo.



Violence: Free Syrian Army fighters carry a fellow fighter who was wounded during clashes near Base 80. Victim Mohammed Fares was injured during the same battle Offensive: The advance into Base 80, a large military position which rebels have held since February, is part of a surge by Assad's forces who are exploiting weaknesses in the opposition Loss: Soldiers carry the body of a fellow rebel who was killed near Aleppo International airport after clashing with Assad's forces