The military carried out five separate strikes, including a rocket attack on the village of Maghara that killed 13 people, the Syrian Observatory for Human Rights said.
The attacks all came shortly before yesterday's iftar, the evening meal at which Muslims break their daytime Ramadan fast, according to the Britain-based group, which relies on a network of activists, lawyers and doctors on the ground across Syria.
The attack in Maghara was the deadliest, but the Observatory also reported six killed in the village of Al-Bara, four in Basamis, three in Kfar Nabl in an air strike and three in Iblin.
Video footage posted online by activists showed harrowing scenes of death and destruction, including fires started by what they said was the rocket strike on Maghara.
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The screams of survivors were heard as the camera panned over the rubble.
"God is great. Where are our Muslim brothers? Where are our Arab brothers?" the activist says as he films residents trying to dig out people trapped beneath the wreckage of their homes.
"This is the iftar of the Muslims in Jabal Zawiya," he said, referring to the hill district where the village lies.
Another man lay dead on the ground, his body and clothes covered in grey dust flecked with blood, his mouth open, his arm curled upwards and his hand lying on his chest.
Residents scooped water into bowls and buckets to try to put out the fires.
The Observatory also reported that at least 13 people were killed in Damascus province last night, when a car bomb exploded outside a police station in the town of Deir Attiya.
The Observatory said at least 18 people were killed in the northeastern district yesterday, three civilians and 15 rebels.
Hundreds of families had been trapped in the area as troops attacked rebel positions.