Al-Nasra's mercenaries launched a rocket attack on houses in al-Wadihi village in southern Aleppo, the SANA news agency said.
The attack killed 12 civilians and wounded 15 others, the agency said.
The Syrian Observatory for Human Rights said the death toll was high because of the number of wounded in critical cases in the village, which is under the control of the regime's forces.
The death toll in northwestern Syria since the start of the military escalation in late April has risen to more than 1,500.
The province of Idlib and Hama and some parts of the provinces of Aleppo and neighboring Lattakia, clashes and shelling between the regime forces and mercenary groups belonging to Turkey, led by Jebhat al-Nasra.
The mercenaries supported by the Turkish occupation control a large part of the province of Idlib and parts of the provinces of Hama, Aleppo and neighboring Latakia. There are also other mercenary groups in the region allied with them, but they call themselves "moderate".