The accident happened on Friday on the highway about a hundred kilometers west of the capital Kathmandu after three in the morning local time.
In Nepal, Asia, more than 60 people were missing on Friday when a landslide caused by heavy rains swept two buses off a highway into a river. Rescue workers are searching for survivors in Chitwan district, officials said.
Three of the bus passengers had made it out of the cars before they plunged into the Trishuli River.
Hours after the search began, rescue patrols had found no trace of the vehicles or their passengers. The flow of the river is very strong, a police spokesman told news agency AFP.
The authorities are not sure of the number of people in the cars, as they have been able to pick up more passengers along the route.
The accident happened on Friday on the highway about a hundred kilometers west of the capital Kathmandu after three in the morning local time.
Annual monsoon rains last from June to September in South Asia.