Islamic State attacked villages near the only useable road that links the government-controlled cities of Aleppo and Homs on Thursday, killing many residents, Syrian state media and a Britain-based war monitor said.
The Syrian Observatory for Human Rights, said 52 people, civilians and fighters on both sides, had been killed and dozens injured. At least 15 were civilians, including five children, and three of them died in execution-style killings, it said.
State-run SANA news agency said that Islamic State fighters killed 20 people in the village of Aqarib al-Safi - east of Hama city before the army and allied militia repulsed the attack.
The Observatory said Islamic State seized Aqarib al-Safi and parts of the nearby village of al-Mabouja as clashes raged on.
The militants said on social media they had captured Aqarib al-Safi.