The landslide occurred Monday night along the Caranavi-La Paz Highway, in the department of La Paz, near the Cajones Bridge, some 100 km north of the capital La Paz.
Police sources said that given the scale of the tragedy, a helicopter was used to transport the most seriously injured people from Caranavi to La Paz.
The landslide triggered by torrential rain swept away the buses when they were traveling that stretch of road linking Caranavi with La Paz, a preliminary report released by Julio Venegas, a traffic officer at the local Minasa bus station.
Rescue workers, including police, firefighters and paramedic units, continued to dig through the mountain of dirt Tuesday, with the number of fatalities possibly rising over the next few hours.
Doctor Adela Noron at the Caranavi Hospital confirmed the arrival of the helicopter to transport the seriously injured to other hospitals as the hospital's capacity to deal with so many emergencies at a time was stretched to the limit.