Two farmers were slain in a region of the southern Brazilian state of Rio Grande do Sul where indigenous people are demanding restitution of what they say are their ancestral lands, authorities said Tuesday.

The brothers Anderson and Alcemar de Souza were found shot and stabbed to death in a cornfield near the town of Faxinalzinho, near the highway where a group of Kaingang Indians held a demonstration on Monday, state police said.

The case was transferred to the Federal Police, the only force in Brazil with legal authority to investigate Indian-related crimes.

This Monday the Indians piled up logs to block a highway leading to Faxinalzinho in a protest demanding that discussions about land-concession procedures be resumed.

When the De Souza brothers removed the logs to clear the road, the band of Indians chased them down and killed them, according to witnesses cited by media outlets.

The regional office of Brazil's Funai indigenous affairs agency asked headquarters to send mediators to help resolve the land conflict, which has gone on for 11 years in this region. EFE