The passenger bus was heading for Pokhara from Gaur in Rautahat district here when it plunged into the swelling Trishuli river, Chitwan Police Chief, Superintendent of Police Basanta Kunwar was quoted as saying by The Kathmandu Post.
Police and locals rescued the injured and pulled out bodies from the wreckage as the bus was submerged.
The injured have been admitted to a nearby hospital in Bharatpur and the deceased are yet to be identified. The search operations for the missing persons is on, he said.
Road accidents in Nepal are generally blamed on poorly maintained vehicles and substandard roads.
Last week, at least 31 people were killed when a crowded bus skidded off the road and fell 300 meters down the hill in central Nepal.
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