The Britain-based Syrian Observatory for Human Rights, which earlier reported an initial toll of 14, said dozens more had been injured in the strikes on the village of Kafr Nabal.
It said the strikes appeared to have been carried out by a Russian warplane.
The Observatory says it determines whose planes carried out raids according to their type, location, flight patterns and the munitions involved.
Hossam Hosber, who witnessed the attack, told AFP "six strikes hit houses and a crowded local market."
More From This Section
It denies that its strikes have caused civilians casualties.
In November, Defence Minister Sergei Shoigu said Russian forces had begun a "major operation" targeting Idlib and Homs provinces.
The northern Idlib province is mostly controlled by a powerful rebel alliance known as the Army of Conquest, which groups Islamist factions with jihadists of the Fateh al-Sham Front, formerly Al-Qaeda's Syrian affiliate.
Most of Homs province is controlled by the Syrian government, but small parts of the countryside in the region are controlled by a range of rebel groups.
More than 300,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests before spiraling into a complex, multi-front war.