Al-Alam correspondent in Syria says the executions were carried out in the city of Deir ez-Zor on Tuesday.
Nearly 200 militants have been killed in the recent infighting between rival terrorist groups in the region.
The deadly clashes have forced 60,000 people to escape their towns in the eastern province.
The new clashes between the rival militant groups continue to rage despite a recent call by al-Qaeda leader Ayman al-Zawahiri to stop the infighting and focus on battling the Syrian government.
Syria has been gripped by deadly violence since March 2011.