Exclusive Report In Photos : Survival in the Amazon

Many indigenous groups, including the Huni Kui, Ashaninka, and Madija, live in villages in the Brazilian rainforest near the border with Peru. Over the past three years, the Ashaninka and Madija say that they have seen more and more incursions on their territory from uncontacted tribes, defined by Survival International as groups who have no peaceful contact with mainstream society. The "Bravos," or "Braves," as uncontacted Indians are called in the region, carry out raids on other villages, putting the communities along the Envira River on permanent alert. Leaders of the Ashaninka tribe have asked the government and NGOs for help in controlling what they consider an encroachment on their area by these uncontacted indigenous groups, stating that the movement of these other tribes is the result of pressure caused by illegal logging across the border in Peru.

A spiritual leader (right) of the Huni Kui Indian tribe performs a ceremony for a sacred samauma (silk-cotton) tree outside the village of Novo Segredo along the Envira river in Brazil's northwestern Acre state on March 9

A view of the Envira river in Huni Kui territory in Brazil's northwestern Acre state on March 8.

Ashaninka Indian children run down the bank of the Envira river to greet a boat near their village of Simpatia in Brazil's northwestern Acre state on March 13.

A spiritual leader (right) of the Huni Kui Indian tribe blows an herbal powder into the nose of a tribal member during a ceremony outside the village of Novo Segredo along the Envira river of Brazil's northwestern Acre state on March 9.

A Madija Indian child walks from one of the village huts which is a frequent target of raids by uncontacted Indians in the village of Dsama, along the Envira river in Brazil's northwestern Acre state on March 11.

Ashaninka siblings pose for a photograph in their village, Simpatia, along the Envira river in Brazil's northwestern Acre state on March 16.

A Huni Kui Indian prepares a drink known as nixi pae or ayahuasca to use in a healing ritual in the village of Novo Segredo along the Envira river of Brazil's northwestern Acre state on March 8.

A view of the Shubua, or house of prayer, in the Huni Kui tribe's village of Me Txanava in Brazil's northwestern Acre state on March 6.

A Huni Kui Indian smokes herbs during a ritual in the village of Novo Segredo along the Envira river of Brazil's northwestern Acre state on March 8.

The boat in which Ashaninka Indian leaders traveled to inspect the limits of their territory is tied to the bank of the Envira river in Brazil's northwestern Acre state on March 15.

Madija Indians clean a caiman to eat on a boat on the Envira river in Brazil's northwestern Acre state on March 14.

A view from inside a river boat on the Envira river near the Huni Kui tribe's village of Me Txanava in Brazil's northwestern Acre state March 8.

Huni Kui Indians sit by the coffin of a newborn baby who died after being born on a boat on the Envira river as the mother tried to reach a hospital, in the village of Me Txanava in Brazil's northwestern Acre state on March 7.

An Ashaninka Indian points his rifle across the Envira river on the grounds of a former government base called the Envira Front of Environmental Protection in Brazil's northwestern Acre state on March 14.

Ashaninka Indian cacique (chief) Txate stands inside a building of the former government base called the Envira Front of Ethno-Environmental Protection along the Envira river in Brazil's northwestern Acre state on March 14.

Ashaninka Indians hold a meeting to discuss their planned occupation of the former government base called the Envira Front of Ethno-Environmental Protection in Kokasul along the Envira river in Brazil's northwestern Acre state on March 16. Brazil's Indian affairs agency (FUNAI) reported to local media that the base was abandoned in 2011 after an attack by armed men from across the border in Peru.

Ashaninka Indians eat a meal at their home in the village of Kokasul along the Envira river in Brazil's northwestern Acre state on March 16.

Binai, son of Cacique Omina of the Madija tribe, plays a ceramic flute made by uncontacted Indians which his father found and gave to him, in Igarape do Anjo in Brazil's northwestern Acre state on March 12.

An Ashaninka Indian holds a shotgun cartridge he found on the grounds of the former government base called the Envira Front of Ethno-Environmental Protection along the Envira river in Brazil's northwestern Acre state on March 14.

An Ashaninka Indian stands next to fresh footprints he found on the grounds of the former government base called the Envira Front of Ethno-Environmental Protection along the Envira river in Brazil's northwestern Acre state on March 14.

Ashaninka Indians pose for a photograph in the village of Kokasul along the Envira river in Brazil's northwestern Acre state on March 16.

An Ashaninka Indian named Uarenco kneels over the grave of his niece who his family buried along the banks of the Envira river two weeks earlier when she died as they navigated the river in search of medical help for her diarrhoea, in Brazil's northwestern Acre state on March 17.

A view of an area of deforested jungle inside the Ashaninka Indian territory in Brazil's northwestern Acre state on March 25.

Ashaninka Indian cacique (chief) Txate observes his tribe's territory from a plane window in Brazil's northwestern Acre state on March 25.

Indians who are considered uncontacted by anthropologists react to a plane flying over their community in the Amazon basin near the Xinane river in Brazil's Acre State, near the border with Peru, on March 25. Many indigenous groups, including the Huni Kui, Ashaninka, and Madija, live in villages in the Brazilian rainforest near the border with Peru.

The Xinane river runs through Ashaninka Indian territory in Brazil's northwestern Acre state on March 25.