Thousands of Indigenous Brazilians from more than 170 ethnic groups demonstrated in the capital on Wednesday ahead of the Supreme Court's landmark ruling on land rights.
Wearing feather headdresses and with their bodies painted, they sang and danced along their 5-kilometre (3-mile) route.
Supreme Court scheduled for Thursday their evaluation of a lower court's ruling that invalidated a claim by some Indigenous people in Santa Catarina state to what they say is their ancestral territory.
The lower court based its decision on allegations the group wasn't occupying the land in October 1988, when Brazil's constitution was signed after the nation's return to democracy.
Indigenous rights activists say the cut-off date ignores the fact many had been forcibly expelled from their ancestral lands, particularly during the military dictatorship, or may not have formal means to prove possession.
The bill also would allow the government to appropriate so-called Indigenous reserves demarcated prior to 1988 if the groups' cultural features have changed.
That could potentially apply to more than 60 areas totaling roughly 400,000 hectares (about 1,500 square miles), which are home to around 70,000 people, according to the institute.