Nine people survived a crash landing on a river in Brazil's Amazon rainforest after native Indians alerted authorities who dispatched a rescue mission, the Brazilian government said today.

The small military plane, which went missing yesterday, was carrying four crew members and seven health officials on a vaccination campaign in remote areas of the jungle.

"We are happy to be alive. The plane stopped in mid-air and we panicked. The pilot plunged the plane into the river," one of the survivors told UOL news after being airlifted to Cruzeiro do Sul, a city in Acre state.

The C-98 Cessna landed on the Itui river, a tributary to the Javari river, in the far western Amazon region. It was not immediately clear what caused the crash.

Members of the Matis tribe spotted the wreckage and notified local authorities. The site is close to where the borders of Brazil, Colombia and Peru meet.

The area is home to a handful of Indian tribes that have little contact with the outside world.

The Cruzeiro do Sul hospital said the survivors appeared to be unhurt. The Brazilian Air Force said divers continued to search the river for the two missing people.

Indians also located and helped in the retrieval operation of a Boeing 737 operated by Brazilian carrier Gol that crashed into the Amazon in 2006, killing all 154 people on board.