The Islamic State (IS) Sunni radical group has executed at least 1,434 people in Syria since it proclaimed an Islamic Caliphate over the territory it controls in Syria and Iraq last June, Syrian Observatory for Human Rights (SOHR) director Rami Abdurrahman told Efe news agency.
In a telephone conversation Monday, Abdurrahman indicated that 884 of those killed were civilians, and some 700 of that total were members of the Al-Shaitat tribe who have been fighting against the IS in the northeastern province of Deir al-Zor.
He explained that militants killed their victims' by gunshots or decapitation.
Besides civilians, the NGO director added, the radical jihadis killed 483 troops fighting for the embattled Syrian regime and 63 members of a rival rebel group called the Nusra Front, an affiliate of the Al Qaeda in Syria, that is vying with IS for control of the north and east.
The IS jihadis have also executed four members of their own organisation who were accused of corruption and other offences.
Abdurrahman said that sometimes the jihadis display the bodies in public squares to "terrorise civilians" and dissuade anyone from opposing them.
The SOHR has documented the executions carried out since Jun 29, when IS declared its caliphate, until now.
Abdurrahman said the aim of the radicals is to frighten the international community and attract potential jihadis to their cause.
The IS claimed Sunday to have beheaded American hostage Peter Kassig in a video posted on the internet.