BAGHDAD — A protest over electricity shortages in oil-rich southern Iraq turned deadly when police opened fire to disperse the crowd on Saturday, killing one protester in a melee that warned of growing anger over the government's failure to provide basic services. More than 3,000 protesters marched through Basra, which suffers from searing summer temperatures that can reach 120 degrees (50 degrees Celsius) and high humidity. They carried banners and chanted angry slogans demanding a solution to the power cuts that persist despite billions of dollars in reconstruction money since the 2003 U.S.-led invasion. It was a scene that has become more frequent across the nation as patience wears thin among Iraqis struggling to cope with less than six hours of electricity a day. But the demonstration turned violent when protesters started throwing stones and advanced on the Basra provincial council building, setting fire to a guard's cabin and prompting government security forces to fire.