Police said that 13 persons died on the spot while two others on their way to a nearby hospital. Another two passengers breathed their last in the hospital.
Five of the injured 15 passengers are said to be in a critical condition. One passenger escaped the accident unhurt, Ekantipur reported.
Police has identified only bus driver and conductor among the deceased. The identity of other deceased passengers has not been ascertained yet.
A team of police have been deployed to the place of accident to rescue the injured passengers, a police official said.