Police say a bus with 31 passengers on board rolled on to its side and burst into flames in southern Bulgaria, killing at least 8 passengers. Plovdiv district police director Todor Chonov said Wednesday that six of the victims died in the incident, while two others died on their way to the hospital. He added that 16 injured people have been taken to nearby hospitals _ two of them in a coma. The bus was traveling from the capital, Sofia, to the Black Sea city of Burgas when it rolled early Wednesday near Plovdiv, some 130 kilometers (81 miles) east of Sofia. Authorities are investigating the cause of the accident, according to a report of the Associated Press.