The Mashco-Piro, a tribe of hunter-gatherers, has had its first recorded contact with the outside world.
Some encounters were friendly with residents of surrounding villages giving them food and tourists handing them clothing.
Other meetings, however, turned violent, leading to the evacuation of entire villages after around 200 tribesmen attacked their residents with bows and arrows, killing livestock and pets and carting off food, pots, pans, machetes and rope.
"All of a sudden, uncontacted Indians who aren’t from the area have started to appear here. Where can they go? They come here. There’s nowhere else," said Jose Carlos Morales of Brazil’s Indian Affairs Department, who has been monitoring the tribes for the past twenty years.
In 2010, a teenager was wounded with a spear, and in 2012, a local guide was killed with a bamboo-tipped arrow.
Peru’s culture ministry has voiced concern that such encounters could also kill Mashco-Piro as well, not just by violence, but because their immune system has never been exposed to common diseases.
"They can be very vulnerable to germs carried by others," said Lorena Prieto, head of the Peruvian culture ministry’s isolated indigenous peoples unit.
After their violent encounters with people outside of their forests, the indigenous peoples' federation for the Madre de Dios reserve (FENAMAD) suggested the Mashco-Piro invasion was "an act of desperation" caused by illegal loggers and drug traffickers invading their land, according to AFP.
FENAMAD condemned tourist visits, raising concerns about why these tribes have decided to venture into the outside world after actively avoiding contact for centuries.
The Peruvian government is currently looking an interpreter among the Yine tribe, who can understand a little of the Mashco-Piros’ language.
Members of the Mashco-Piro in south-eastern Peru, one of around 100 uncontacted indigenous tribes in the world. pic.twitter.com/jnbi0Asfsz— Malaika (@Bandja) February 8, 2015
The illegal loggers and gold miners have destroyed an estimated 55,000 hectares (136,000 acres) of forest in the region, driving a tribe of 800 people living in the Madre de Dios in southern Peru out of their forest.
The region inhabits two other isolated groups, about 150 Machiguengas and 300 Nahuas, who are also in danger of losing their home, considering Madre de Dios has the highest output of illegally mined gold in Peru, reported AFP.
"Isolated indigenous peoples have rights protected by the United Nations, including the right to decide to live in isolation, which the state must respect and protect," Prieto said.