Rami Abdelrahman, the head of the so-called British-based Observatory for Human Rights, said on Wednesday that these types of incidents were common in rebel-held areas and the victims were almost civilians.

Abdelrahman obtained pictures of a man who he said had been tortured by the militants. The man's legs had the skin torn open in several places. His back was covered in open lash marks.

The man told the Observatory he had sustained the injuries while being detained for three days by the terrorist.

Other residents told the group that the unit of Ahrar Suriya, which operates near Aleppo's district of Ashrafiyeh, had forced refugees as well as local residents to pay protection money.

Torture, kidnapping and summary killings by terrorists have become a daily aspect of the insurgency in Syria.

Human rights violations committed by armed rebels in Syria have been documented by the United Nations.

Syria has been facing an armed insurgency since March 2011 that has left thousands of people dead. The Syrian government says the insurgency is being orchestrated from outside the country.