Brazilian Indians gathering to mark the official opening of a new reservation have been trapped in a remote village after its bridge caught fire.
Authorities believe that white settlers opposed to the creation of the huge Raposa Serra do Sol reservation deliberately set the bridge on fire.
It is the only access into Maturuca, a village in the northern state of Roraima near the Guyanese border.
Brazil agreed to create the reservation amid much controversy in April.
Some 3,500 people had gathered at Maturuca for the celebrations on Thursday.
Brazilian media quoted officials as saying the fire appeared to have been a deliberate act of sabotage.
Rice farmers who moved to the area over the decades strongly opposed having a reservation despite government promises that they would be moved to alternative land.
Called "the land of the fox and mountain of the sun" by the 12,000 Indians who live there, Raposa Serra Do Sol covers 17,000 sq km (6,500 square miles).
It was created after 30 years of campaigns by the Indians, which led to bitter conflicts with settlers and farmers in which at least a dozen Indians were reportedly killed in conflicts with miners and settlers.