“Fourteen bodies were recovered while 15 injured are receiving treatment at local hospitals,” a district official told Xinhua news agency.
The accident took place at 5 a.m. The bus, carrying nearly 40 passengers, was en route to Kathmandu from Rajbiraj.
The police have intensified rescue operations and the toll was expected to rise, the official added.
Authorities have not yet been able to pull the bus out of the river.