BEIRUT (Reuters) - The U.S.-backed Syrian Democratic Forces alliance (SDF) has launched an operation against Islamic State militants in the north of Deir al-Zor province in eastern Syria, a statement said on Saturday. The statement from the Deir al-Zor Military Council, fighting as part of the SDF, said assaults would aim to drive the jihadist militants out of areas they hold north and east of the Euphrates river. 