By Steve Kingstone BBC correspondent in Sao Paulo

The Indians have vowed to fight to the death for the farms

A team of 600 officers will clear the area but the police have not said when they will move in as tension between the Indians and farmers rises.

The Indians, who come from the Guarani and Kaiowa tribes, began invading the farms shortly before Christmas.

They have refused to go quietly and their leaders have promised to fight to the death in defending the farms.

Last week a federal judge sided with the farmers and gave the indigenous people three days to leave the land.

The Indians are camped out at 14 farms in the state of Mato Grosso do Sul, near Brazil's border with Paraguay.

They say the land ancestrally belongs to them.

On Wednesday afternoon a tense stand-off developed as displaced farmers returned to confront the Indians, who wore tribal dress and carried bows and arrows.

The farmers fired shots into the air but the police soon restored order.

Last week a federal judge sided with the farmers and gave the indigenous people three working days to leave the land.

That time period has now elapsed and the local authorities have assembled 600 officers to evict the Indians.

They will receive logistical help from the army.

Local hospitals are on stand-by in the event of injuries.