At least 15 passengers were killed and 12 others injured when a bus overturned near Burhan Interchange, Attock this morning. According to sources, bus was full of passengers and suddenly it went out of control and rolled over. The accident took place due to the drivers negligence. According to bystanders, dead bodies and the injured were shifted to hospital by the local people. A pool of blood was scattered all around. Condition of some of the injured was stated to be critical, hospital sources said.