At least 18 civilians were killed and 40 wounded in "probably Russian" air strikes on a rebel-held town in northwestern Syria on Sunday, a monitoring group said.The strikes hit the Idlib province town of Ariha, which is controlled by the Army of Conquest, a rebel alliance, 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.A longtime ally of Damascus, Moscow escalated its support to Bashar al-Assad on September 30 with an air campaign aimed at bolstering regime positions and backing ground operations by Syrian government troops.