The photographs were taken near the Brazil-Peru border from a series of flights over the remote region. Survival International, a human rights group that campaigns for indigenous groups, conducted the search and believes the photographs are evidence that such indigenous groups still exist.
"We did the overflight to show [the tribe's] houses, to show they are there, to show they exist," said José Carlos dos Reis Meirelles Júnior in a statement released by Survival International.
Meirelles works for FUNAI, Brazil's Indian affairs department. "This is very important because there are some who doubt their existence."
Meirelles, who was inside the helicopter when the revealing pictures were taken, believes that this tribe should be kept isolated as long as possible:
"While they keep aiming arrows at us, everything will be OK," he said. "The day they start behaving nicely that will the day they will be exterminated."
Pictures obtained by Survival International's website show men from the tribe covered in bright red paint with bows taking aim while another man in black looks on from the side.
Other photos from the expedition show a settlement with thatched roof homes surrounded by dense forest. Around 15 men in red are shown taking aim at the aircraft in which the camera was mounted on.
The tribe is increasing in numbers, says Meirelles but notes that un-contacted groups in other regions of the Amazon are in danger of coming to conflict with each other due to illegal logging.
Of the world's 100 known un-contacted tribes, over half are in Brazil or Peru and are in danger of being driven off their land, says Survival International.
Also a threat to isolated groups is the possibility of contracting introduced illnesses which may become fatal. In 2003, over 65 percent of Columbia's Nukaak Maku tribe died of disease after contact was made by explorers.
"The world needs to wake up to this, and ensure that their territory is protected in accordance with international law," says Stephen Corry, director of Survival International. "Otherwise, they will soon be made extinct."
Contact of the Brazilian Indian with the outside world has been a disaster. Brazil has today about 350,000 Indians compared to the 5 million that lived in the country at the time of the arrival of the Portuguese in 1500.
"In 508 years of history, of the thousands of tribes that exist, none of them was able to adapt well to the Brazilian society," says Sydney Possuelo, who devised the FUNAI's office responsible for dealing with isolated Indian, at the time he worked with that state organization.
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