By Kanishka Singh (Reuters) -Mass shootings in Philadelphia, Pennsylvania, and Chattanooga, Tennessee, left at least six people dead and more than 25 wounded, police said on Sunday in the latest cases of gun violence after recent massacres in Texas, New York and Oklahoma. Multiple shooters opened fire in Philadelphia’s busy South Street, an area filled with bars and restaurants, around midnight on Saturday. Two men and a woman were killed, officials said. A surveillance video from the shooting showed people on a crowded street running in panic in the closing moments of the 22-second clip, pres…