BRASILIA -- Eight people drowned and 20 were missing, after a boat sank as it ferried around 70 mainly young people to a dance festival in Brazil's Amazon basin, media reported Sunday.

The ferry, the Orlandina, sank Saturday in the River Madeira, near the city of Humaita in Rondonia state.

According to port authorities quoted by Globo news, rain and high winds drove the vessel toward rocks on the banks of the river, and low water levels caused it to sink rapidly, AFP reported.

Many children and teenagers were aboard the ferry, heading to a folk dancing festival at Calha do Rio Madeira.

State port authority commander Sebastiao Coelho ruled out overloading of the vessel as cause of the sinking.