Covered in war paint, brandishing bows and arrows and old hunting rifles, more than 3,000 Guarani Indians have forcibly occupied farms in Western Brazil, sparking violent confrontations with farmers.
There is a long history of violence in land disputes in southern Brazil
The dispute is rapidly becoming a test case posing a serious dilemma for Brazil's new Workers' Party President Luis Inacio Lula da Silva.
It is being watched by Indian groups with land claims around Brazil - as well as by farmers' organisations who fear it could start a wave of similar confrontations.
The Guarani occupied 14 farms, which they claim as ancestral lands, in December, driving the farmers out.
They want the government to declare the area an Indian reservation.
Now they have proposed a settlement - from next week they will restrict their occupation to the three largest farms. Farmers can return to tend their cattle while the Brazilian Government marks out an enlarged Indian reserve.
But it is not clear whether the farmers will accept the deal - many stand to lose everything, because Brazilian law does not entitle them to compensation if their farms are declared Indian land.
They have been protesting to demand the government evict the Indians - or else some of them warn they will do the job themselves.
The two sides have already come to blows once - when the farmers gathered on a river Bridge close by the farms.
Thinking they were about to enter - the Guarani advanced down a dusty track towards them.
They were a fearsome sight - whooping and dancing a war dance - many wearing black masks with feathers.
Some rode bareback on horses taken from the occupied ranches.
The farmers, clearly terrified, fired pistols over the Guarani's heads.
"Go on. Kill us," the Guarani taunted them. "We're only Indians!"
The Guarani say they lost the land more than 50 years ago - when the government of the time gave it away in land grants to white settlers.
They were pushed into a reservation sandwiched in the middle of the farms, where 3,500 of them now live with only one acre of land per head.
But the Guarani's anger runs deeper.
When the Portuguese arrived their forests covered a large area of Brazil.
They were the first Indian group to be subjugated by Europeans.
Today almost their whole area has been turned into a prairie of soy and cattle ranches.
Seventy-four-year-old Ava Vera Jui says he remembers a graveyard in what is now a commercial farm.
"We used to bury our dead covered in the leaves of coconut palms," he said.
"We were free then to move around in this, our land."
Based on testimony like his, the government agency in charge of Indian affairs in Brazil three years ago recommended the Guarani be given the land.
But the case has since become bogged down in bureaucracy.
Guarani leaders say they are using force now because they have lost patience.
But they are also hoping for a sympathetic ear from Brazilīs president, known as Lula, who in the past supported such land occupations.
"Our hearts have been crushed by so many promises," says Guarani leader, Ava Tupa Xirino.
"We believe Lula will help. He is a powerful man. We all voted for him. If he gives us our land he will be our father."
The fact that the central government appears to be supporting the Indians has infuriated the farmers, who complain no-one is protecting them.
All the 14 farms affected, totalling more than 22,000 acres, were bought by the current owners long after the Guarani lost the land.
The farmers say they bought the land in good faith
and say the whole society should have to pay for an injustice done to the Indians decades ago, not they alone.
They also tell stories of farmers being mistreated by the Indians.
"They were very aggressive," says Alberi de Lima, who only bought his land a year ago. He described how the Indians came in a large group to the farm.
"They did not let me talk to them. They said this was their land - but I have land titles."
The land in this region never used to earn a great deal of
But the arrival of soy as the main crop in the last year means profits have suddenly increased tenfold, making
the farms much more valuable.
For the moment the Guarani believe they have won the first round of what promises to be a long battle.