Small groups of Syrians are hunting down Islamic State fighters in one of their main strongholds in eastern Syria in a new guerrilla campaign that has emerged as a response to the Islamists' growing brutality.
The main aim is to generate fear in Islamic State's ranks, said the head of "White Shroud" - a group that says it has killed more than 100 Islamic State fighters in attacks in Deir al-Zor province in recent months.
The name reflects that aim: White Shroud is a reference to the death shroud it says awaits Islamic State fighters responsible for crimes against the Syrian people, said the group's leader, Abu Aboud, in an interview via Skype.
As the United States advances plans to train and equip the moderate opposition to President Bashar al-Assad as part of its strategy to tackle Islamic State, the appearance of such groups shows how it has generated new enemies on the ground.
Abu Aboud, who declined to give his real name for security reasons, was a commander in an anti-Assad insurgent group crushed by the better armed and financed Islamic State as it seized almost full control of Deir al-Zor earlier this year.
The small band he now leads is in no position to deal a major blow to Islamic State. But it does pose an extra challenge as the United States and its allies target the group in air strikes in both Syria and Iraq.