A Syrian military air strike killed and wounded dozens of people when it hit an olive oil press near the northern city of Idlib.
Activists said at least 20 people were killed and 50 wounded in the attack near the Abu Hilal olive oil press.
The Syrian Observatory for Human Rights said it could only confirm five deaths.
Syria's northern provinces, including Idlib, have been subjected to heavy air assaults by government forces against rebels fighting to topple President Bashar al-Assad.
Activists said it was unclear if there was any rebel target in the area and that the victims were civilians, but acknowledged there were opposition fighters in the area.
They said a jet fired two barrel bombs that hit the press, and that rebels gave medical treatment and helped evacuate victims.
The British-based Observatory, which has a network of activists across Syria, said that so far it has confirmed the deaths of five people, with five wounded.
Activist reports are difficult to verify as the government restricts access to foreign media outlets.