At least 17 people, including children, have been killed by regime forces in a shelter in the town of Nabuk, the Syrian Observatory for Human Rights says.
Citing activists inside the town north of Damascus, the watchdog said on Friday the bodies of the civilians were found in Nabuk's Al-Fatah district.
It was unclear when the 17 civilians had been killed, and the Observatory called for the International Committee of the Red Cross to be given access to the area.
Regime troops and rebels have been battling for days in Nabuk, as the Syrian army fights to capture the Qalamoun region north of Damascus.
The army has seized nearby Qara and Deir Attiyeh, which lie north of Nabuk along the key Damascus-Homs highway.
But it has also seen rebels seize the town of Maalula, a historic Christian hamlet in Qalamoun, as the fighting in Nabuk continues.
The Observatory said that elsewhere in the country at least 16 people were killed in regime air raids on the town of Bazaa in northern Aleppo.
The group says six children and five women are among the dead in the air strikes.
Syrian state television, meanwhile, said at least three people had been killed and 15 wounded by rebel rocket fire on regime-held districts of Aleppo city.
