The Islamic State group killed more than 50 people in an attack on two government-held villages in central Syria's Hama province on Thursday, a monitor said.
The Britain-based Syrian Observatory for Human Rights said the attack on the villages of Aqareb and al-Mabujeh killed at least 15 civilians and 27 pro-government fighters.
It said another 10 bodies were yet to be identified as government fighters or local residents.
IS also lost 15 fighters in the dawn attack on the two villages in the east of the province, the monitor said.
State news agency SANA reported the attack, giving a toll of 20 civilians killed in Aqareb, without mention of al-Mabujeh.
It said most of the civilians had been beheaded and mutilated.
Observatory director Rami Abdel Rahman said at least three of the civilians killed in the attack, a man and his two children, had been executed.
It was unclear if others had also been executed or were killed in fighting.
The Observatory said IS had seized control of Aqareb and part of al-Mabujeh.