Free Syrian Army fighters erect the Syrian opposition flag atop a former base used by fighters from the Islamic State in Iraq and the Levant (ISIL), after it was captured by rival rebel forces in Manbij town in Aleppo January 8, 2014. An al Qaeda affiliate based in Iraq and Syria has vowed to crush opposition groups it has been confronting in the worst outbreak of infighting among rebels since the start of the uprising against President Bashar al-Assad. Picture taken January 8, 2014. REUTERS/Nashwan Marzouk (SYRIA – Tags: POLITICS CIVIL UNREST CONFLICT)