Hezbollah and the Syrian branch of al Qaeda have fought a deadly five-day battle in Syria near the border with Leba**n, a Hezbollah source and a fighter for the Nusra Front said on Thursday. Hezbollah is a Shi'ite Muslim militant group that has fought alongside troops loyal to President Bashar al-Assad in Syria's civil war, **w in its fourth year. Al Qaeda's Nusra Front is a Sunni militia that considers all Shi'ites heretics deserving death.