The raids by unidentified warplanes targeted a mosque in Aleppo province during evening prayers, killing 42 people, most of them civilians,” said the head of the Britain-based Observatory Rami Abdel Rahman.
“More than 100 people were wounded,” he said, adding that many were still trapped under the collapsed mosque in the village of Al-Jineh, just over 30 kilometres (20 miles) west of Aleppo.
The village is held by rebel and Islamist groups, but no jihadist factions are present.
Rescue workers struggled to pull survivors from rubble, and dozens of residents were still unaccounted for, the Observatory said.
Abu Muhammed, a village resident, told AFP that he “heard powerful explosions when the mosque was hit. It was right after the prayer at a time where there is usually religious lessons for men in it”. Online banking solution video
“I saw 15 bodies and lots of body parts in the debris when I arrived. We couldn’t even recognise some of the bodies,” he added.
An AFP reporter at the scene said rescuers earlier left the wreckage site but were forced to double back when they heard moaning coming from the debris.
Footage published by Halab Today, an online media group focused on news in Aleppo, showed piles of rubble where the mosque allegedly stood.
More than 320,000 people have been killed in Syria since the conflict began six years ago with anti-government protests.