Kathmandu  - At least 16 people were killed and more than two dozen injured Sunday when a passenger bus plunged off a mountain highway in western Nepal, police said.

The bus fell about 250 metres off the narrow highway in the Arghakhanchi district, about 350 kilometres west of Kathmandu.

Police said most of the victims died after being crushed inside the mangled remains of the bus.

Police officer Radhe Shyam Singh said 25 people were injured in the accident and half of them were in serious condition.

The road where the accident occurred was unpaved and its condition was made worse by landslides caused by heavy rains last month, police said.

The cause of the accident was not immediately known, but police said the bad road condition might be to blame.

Road accidents involving public buses are common in Nepal because they are often overcrowded and poorly maintained.

Police also said a majority of the accidents are due to the recklessness of drivers who fail to take safety precautions on dangerous mountain highways.  (dpa)