Brazilian Waiapi walk through an indigenous reserve in Amapa state in 2017. Brazil's tribal peoples have long faced pressure from miners, ranchers and loggers. - AFP

Armed miners have reportedly invaded a village in a remote part of Brazil and killed a tribal leader.

Villagers fled but were planning to return, sparking fears of a "bloodbath," according to local reports.

The violence began last week when the indigenous leader was reportedly stabbed to death in an area belonging to the Waiapi tribe in Amapa state, in the north of the country.

It came as around 50 miners, known as "garimpeiros," were said to have overrun the Waiapi village of Mariry.

The leader's body was reportedly found with stab wounds in a river.

The village is 186 miles from the state capital and a team of police departed to investigate.

Randolfe Rodrigues, an opposition senator from Amapa, writing on his Facebook page, said: "The situation is urgent."

He warned of a "bloodbath" and added: "This is the first violent invasion in 30 years since the demarcation of the indigenous reserves in Amapa."

Jawaruwa Waiapi, a Wajãpi leader, said the government should send soldiers because the miners were armed with rifles. He said: "We're in danger."

There are more than 1,000 Waiapi living in remote villages near the Brazilian border with French Guiana.

Brazil's tribal peoples have long faced pressure from miners, ranchers and loggers.

Activists say the threats have intensified since Jair Bolsonaro, the pro-business president, 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, and access by outsiders is strictly regulated.

Reports of the attack emerged as Mr Bolsonaro once again defended mining in the Amazon, highlighting the "absurd quantity of minerals" there. Mr Bolsonaro said he was looking for the "first world" to help Brazil exploit the areas.