A series of airstrikes in eastern Syria on Tuesday killed more than a dozen people, including an Iranian military adviser and a team member working for the UN’s World Health Organization, officials and reports said. It was not immediately clear who was behind the airstrikes in Syria’s eastern province of Deir Az-Zour that borders Iraq. The British-based Syrian Observatory for Human Rights, an opposition war monitor, said the strikes killed 15 people including an Iranian adviser with Tehran’s paramilitary Revolutionary Guard, two of his bodyguards as well as nine Iraqi fighters from an Iran-bac…