Syrian government troops in Aleppo have been reportedly going door-to-door killing civilians Tuesday in the holdout city’s sole remaining rebel-held enclave—a development the United Nations human-rights office termed “a complete meltdown of humanity.” The UN office said it had reliable evidence that at least 82 civilians, including 11 women and 13 children, have been shot on sight by pro-government forces. Further reports say the atrocities have left bodies lining the streets and children being set on fire. “We’re filled with the deepest foreboding for those who remain in this last hellish corner” of eastern Aleppo, said spokesman Rupert Colville. Days of artillery bombardments and airstrikes by regime and Russian forces have pinned as many as 100,000 civilians into a few square miles in what was Syria’s largest city before its five-year civil war. The Russian military said Monday that 98 percent of the rebel stronghold had been retaken, and a Kremlin spokesman blamed the violence on “terrorist groups”—its code word for Syrian rebels. The UN and the International Committee of the Red Cross are pleading with Moscow and President Bashar al-Assad to allow a safe passage for civilians to flee the area.