Kathmandu | A passenger bus skidded off the main highway and plunged into a swollen river in Nepal's Bagmati province on Wednesday, killing at least eight people and leaving at least 15 others injured, according to a media report.

The accident happened when the bus en route to the scenic city of Pokhara from Kathmandu veered off and fell into the Trishuli River at Chalise in the province's Dhading district, myRepublica.com reported.

"In the accident, at least eight people have been killed and 15 more injured. The number of those killed might go up. Rescue is ongoing," Deputy Superintendent of Police Santulal Prasad Jaiswar at the District Police Office, Dhading, was quoted as saying in the report.

He said that the bus was partly submerged in the Trishuli River after the accident, but rescuers were able to pull out many of the passengers alive from the wreckage.

The river had been swollen by continuous rainfall during the monsoon season.

Highway accidents in Nepal, which are mostly covered by mountains, are mostly blamed on poorly maintained vehicles and roads.