The point of contention is a bill before the legislature that would transfer authority to set aside land for indigenous groups from the Brazilian presidency to the parliament.
"By bringing the decision to demarcate lands to Congress, technical criteria will be replaced by political ones," said Adelar Cupinski, a legal adviser to the Indigenous Missionary Council.
Six demonstrators were arrested at the protest yesterday, while Globo television showed a policeman getting shot in the foot with an arrow although the injury was reported as slight.
The speaker of the chamber of deputies, Henrique Eduardo Alves, pledged to postpone debate on the bill until some kind of agreement is reached.
The protesters remained all day yesterday inside the legislature and at night stormed into a plenary session, dancing in their traditional dress before being forced to leave.