HOMS, Syria—Regime loyalists here voiced fury over a United Nations humanitarian relief mission for a rebel-held enclave in their city, accusing the organization of bias against minorities that support President Bashar al-Assad. The U.N. said Monday that it was extending the relief mission for the old quarter of Homs for three more days. It has already evacuated more than 1,000 people and delivered desperately needed food while its convoys came under mortar and sniper fire on their way into the besieged enclave. At least 11 people have been killed in violence around the operation since it began on Friday, the U.N. said. Members of the Mr. Assad’s Alawite sect, an offshoot of Shiite Islam and a minority in Syria that dominates the regime, accused the U.N. of being far more concerned about taking in food and medicine for rebels and civilians than determining the whereabouts of some 740 missing […]