Rocket fire has killed 12 civilians in a regime-held village in north-western Syria, state news agency SANA has said blaming former al-Qaeda affiliate Hayat Tahrir al-Sham for the attack.
SANA said 15 people were also wounded late on Sunday in the attack on Al-Wadihi village south of Aleppo city and said HTS, which controls parts of Aleppo's countryside as well as most of neighbouring Idlib, was responsible.
It published graphic pictures purporting to show some of the victims in a hospital in the aftermath of the attack, including of bandaged men and children lying on stretchers, thick blankets covering their bodies.
Clashes in northwest Syria kill 35 fighters - monitor
The Syrian Observatory for Human Rights reported the same death toll - saying five children were among those killed - and also blamed jihadists based in rural Aleppo for the attack.
But the Britain-based monitor did not specify whether HTS or other allied jihadist groups were responsible.
Massive regime offensive
The attack came as Syrian government forces have been locked in clashes with HTS fighters in nearby Hama province.
More than 35 combatants, mostly regime forces, were killed on Saturday in battles in Hama's countryside, according to the Observatory.
Parts of Aleppo, Hama and Idlib are supposed to be protected from a massive regime offensive by a buffer zone deal that Russia and Turkey signed in September.
But it was never fully implemented as jihadists refused to withdraw from a planned demilitarised zone.
In January, HTS extended its administrative control over the region, which includes most of Idlib province as well as adjacent slivers of Latakia, Hama and Aleppo provinces.
The Syrian government and Russia have upped their bombardment of the region since late April, killing nearly 400 civilians, according to the Observatory.
Syria's war has killed more than 370 000 people and displaced millions since it started in 2011 with the repression of anti-government protests.