The strikes hit the Idlib province town of Ariha, which is controlled by the Army of Conquest, a rebel alliance of mainly Islamist groups, including Al-Qaeda affiliate Al-Nusra Front, the Syrian Observatory for Human Rights said.
Several areas of the town were hit and rescue operations are under way with several critically wounded, the Britain-based group said.
The Army of Conquest alliance seized Ariha in May after heavy fighting with regime forces.
Russia launched a bombing campaign in Syria on September 30. It says it targets the Islamic State group and other "terrorists", but critics accuse it of targeting moderate and Islamist rebel fighters more than IS.