Police in Brazil were on Sunday investigating the reported killing of an indigenous leader and invasion of a remote village by armed miners in the county's north, a spokesman said.
The violence began earlier in the week when the indigenous leader was reportedly stabbed to death in an area belonging to the Waiapi tribe in Amapa state.
On Friday, around 50 miners, known as "garimpeiros," overran the Waiapi village of Mariry, prompting residents to flee, local media said.
A team of federal police investigators departed Saturday for the village situated nearly 300 kilometers (186 miles) from the state capital Macapa, a police spokesman who declined to be named told AFP.
The remoteness of the village is hampering communications, he said.
However local media reported some residents have returned to the village to retake it, prompting fears of a "bloodbath."
"The situation is urgent," said Randolfe Rodrigues, an opposition senator from Amapa, on his official Facebook page.
Brazil's tribal peoples have long faced pressure from miners, ranchers and loggers, but activists say the threats have intensified under pro-business President Jair Bolsonaro, who took power in January vowing to increase development in the Amazon rainforest.
The Waiapi live deep inside the Amazon in an area rich in gold, manganese, iron and copper.
Their territory is one of hundreds Brazil's government demarcated in the 1980s for the exclusive use of indigenous inhabitants. Access by outsiders is strictly regulated.
Reports of the attack emerged as Bolsonaro once again defended mining in the Amazon on Saturday, highlighting the "absurd quantity of minerals" there.
Bolsonaro said he was looking for the "first world" to help Brazil exploit the areas.