Youth gang riots in the Swedish capital Stockholm have entered fifth straight night. Hundreds of mostly immigrant teenagers tore through the suburbs, smashing windows and burning cars in the country’s worst outbreak of violence in years. At least six vehicles were torched throughout the city late on Thursday while the police called for reinforcements from other Swedish cities bracing for further unrest. Firefighters were putting out flames that engulfed several cars and a school in immigrant-dominated areas of Stockholm. The night before, the fire brigades were called to some 90 different blazes. On the fourth night of violence, youths torched...