At least 15 people have been killed and 25 others injured when a bus carrying marriage party veered off a hilly road and fell into a river in south-western Nepal.

The ill-fated bus met with the accident at Chidapani village of Palpa district along the Siddhartha Highway on Sunday night, police said.

Twelve people died on the spot while three others succumbed to injuries at Lumbini Medical College Hospital, police added.

The bus driver was also killed in the accident and the vehicle was completely damaged.

Four injured are said to be critical. Both the bridegroom and bride were also injured but are safe.

The accident occurred due to drunken drive, police said.