Militants from the the Islamic State group, also known as the Islamic State of Iraq and Syria (Isis) or the Islamic State of Iraq and the Levant (Isil) have reportedly burnt six people alive in barrels of tar after they were "convicted" by a Sharia court of cooperating with enemies of the extremist group also known as Daesh in the Middle East. The incident is said to have taken place in the city of Mosul in northern Iraq, which is one of the biggest strongholds of Isis in the country.

Sources told Iraqi News: "ISIS executed six persons in Mosul for collaborating with Nineveh Operations Command. The death sentence was issued Isis Sharia Court." Nineveh Liberation Operations Command, also known as Nineveh Operations Command, is one of the rebel groups fighting to drive Daesh out of Mosul and Nineveh in Iraq.

The sources also said: "The six persons were placed inside tanks containing boiling tar and the execution was carried out in one of Isis headquarters at al-Shora. The execution took place in public and it was done with an aim of inciting fear among the citizens."

This is the latest in the string of atrocities committed by Isis in Iraq and Syria in order to keep people in check with the tool of fear. Although executions have been one instrument in wielding the weapon of fear, the methods of execution Isis militants have used have become progressively more violent and deranged. As if beheadings were not enough, there were instances when people were burnt alive in a cage, while others were crucified and had their hearts cut out.

And the offences that led to convictions that entailed the death sentence have become progressively wider in range, from not fasting during Ramadan to anything and everything the group considers blasphemy. In a more recent example, the Syrian Observatory for Human Rights reported that Isis executed a man in the Deir Ezzor province of Syria immediately after he was caught wearing women's clothes, possibly to conceal his identity while escaping.

The latest executions in Iraq come in the backdrop of Isis increasingly losing ground in Syria, where it was recently driven out of Manbij city, but took with it 2,000 people to use as "human shields" on their journey towards Aleppo city. They reportedly freed many of these people later.