Brazil’s highest court weighed arguments on Wednesday over a cut-off date for land claimed by indigenous people.
This comes as far-right President Jair Bolsonaro advocates deforestation to expand farmland, saying too few indigenous people live on too much land.
Wednesday's case rose to the Supreme Court in an appeal by the Xokleng people, who were driven from their land over a century ago.
They’ve challenged what they call the state’s overly narrow interpretation of indigenous rights and have protested outside courts as they wait for a decision.
The government argued that native communities can only claim land occupied by their people in 1988 when Brazil’s constitution was ratified.
A lawyer representing the largest indigenous organization, said the constitution does not lay out a timeframe for ancestral land guarantees.
Luiz Eloy Amado said, "The land question is fundamental for Brazil's indigenous people.”
Amado added some 800 claims would be stalled if the 1988 deadline is accepted by the court.
The case is expected to drag on for days.
The court adjourned until Thursday, when 18 speakers are expected to discuss the issue before justices.