in this old village, it's hard to believe there are people on this planet who haven't had any contact whatsoever with the modern world.

On Thursday members of the world's last uncontacted tribes were spotted near the border of Brazil and Peru. Rare evidence that these groups exist came in the form of aerial photographs that show the people painted bright red and carrying bows and arrows.

A picture shows two painted men pointing their arrows at the aircraft carrying the photographer while a third man looks on. Another image shows a group of about 15 people standing near some thatched huts poised to shoot their arrows at the plane.

Illegal logging is putting this group's secluded existence at risk, according to a Brazilian official.

There are more than 100 uncontacted tribes worldwide and more than half of them live in Brazil and Peru, according to the group Survival International. Many of these people are being forced off their land and are dying from new diseases.

RIO DE JANEIRO - Dramatic photographs of previously unfound Amazon Indians have highlighted the precariousness of the few remaining "lost" tribes and the dangers they face from contact with outsiders.

The bow-and-arrow wielding Indians in the pictures released on Thursday are likely the remnants of a larger tribe who were forced deeper into the forest by encroaching settlement, experts said.

Rather than being "lost", they have likely had plenty of contact with other indigenous groups over the years, said Thomas Lovejoy, an Amazon expert who is president of The Heinz Center in Washington.

"I think there is an ethical question whether you can in the end keep them from any contact and I think the answer to that is no," Lovejoy said.

"The right answer is to have the kind of contact and change that the tribes themselves manage the pace of it."

The Brazil-Peru border area is one of the world's last refuges for such groups, with more than 50 uncontacted tribes thought to live there out of the estimated 100 worldwide.

They are increasingly at risk from development, especially on the Peruvian side which has been slower than Brazil to recognize protected areas for indigenous people.

Jose Carlos Meirelles, an official with Brazil's Indian protection agency who was on the helicopter that overflew the tribe, said they should be left alone as much as possible.

"While we are getting arrows in the face, it's fine," he told Brazil's Globo newspaper. "The day that they are well-behaved, they are finished."

Contact with outsiders has historically been disastrous for Brazil's Indians, who now number about 350,000 compared to up to 5 million when the first Europeans arrived.

"In 508 years of history, out of the thousands of tribes that exist none have adapted well to society in Brazil," said Sydney Possuelo, a former official with Brazil's Indian protection agency who founded its isolated tribes department.

In recent years, though, tribes like the Yanomami have succeeded in winning greater protection by becoming more politically organized and forming links with foreign conservationists.

"It's not about making that decision for them. It's about making time and space to make that decision themselves," said David Hill of the Survival International group.

More than half of the Murunahua tribe in Peru died of colds and other illness after they were contacted as a result of development for the first time in 1996, Hill said.

Sightings of such tribes are not uncommon, occurring once every few years in the Brazil-Peru border area where there are estimated to be more than 50 out of the total global number of 100 uncontacted tribes.

In 1998, a 200-strong tribe was discovered by Possuelo living in huts under the forest canopy, also in Acre state near the Brazil-Peru border.

In September last year, ecologists looking for illegal loggers in Peru spotted a little-known nomadic tribe deep in the Amazon.

The sighting underscored worries among rights groups that oil and gas exploration being pushed by the Peruvian government, as well as logging, is putting tribes at risk.

Peru has no equivalent to Brazil's long-standing Indian affairs department, which has a policy of no contact with unknown tribes.

"There is a lot of logging going on over on the Peruvian side," Hill said. "It's had all kinds of effects on the groups living there, particularly on the uncontacted groups -- it's led to violent conflicts and deaths."

In May, Peru's petroleum agency Perupetro said it would exclude areas where isolated tribes live from an auction of oil and gas concessions. Perupetro had been under pressure to limit exploration activities near tribal areas, and had cast doubt on the existence of isolated groups, angering activists.

One of South America's few remaining uncontacted indigenous tribes has been spotted and photographed on the border between Brazil and Peru.

The Brazilian government says it took the images to prove the tribe exists and help protect its land.

The pictures, taken from an aeroplane, show red-painted tribe members brandishing bows and arrows.

More than half the world's 100 uncontacted tribes live in Brazil or Peru, Survival International says.

Stephen Corry, the director of the group - which supports tribal people around the world - said such tribes would "soon be made extinct" if their land was not protected.

'Monumental crime'

Survival International says that although this particular group is increasing in number, others in the area are at risk from illegal logging.

The photos were taken during several flights over one of the most remote parts of the Amazon rainforest in Brazil's Acre region.

They show tribe members outside thatched huts, surrounded by the dense jungle, pointing bows and arrows up at the camera.

"We did the overflight to show their houses, to show they are there, to show they exist," the group quoted Jose Carlos dos Reis Meirelles Junior, an official in the Brazilian government's Indian affairs department, as saying.

"This is very important because there are some who doubt their existence."

He described the threats to such tribes and their land as "a monumental crime against the natural world" and "further testimony to the complete irrationality with which we, the 'civilised' ones, treat the world".

Disease is also a risk, as members of tribal groups that have been contacted in the past have died of illnesses that they have no defence against, ranging from chicken pox to the common cold.

One of the world's last 'uncontacted' tribes has been photographed from the air by the Brazilian government on its border with Peru.

The pictures, which show red-daubed Indians wielding bows and arrows, were taken during flights over the remotest parts of the Amazon rainforest in Brazil's Acre state.

The warriors had a "strong and healthy appearance", a statement said.

Funai, the Brazilian government's Indian affairs department, said it took the photos to prove to the world that uncontacted tribes did exist.

"We did the overflight to show their houses, to show they are there, to show they exist," said Funai's Jose Carlos dos Reis Meirelles Junior.

"This is very important because there are some who doubt their existence."

Mr Meirelles said the uncontacted tribe, one of 100 across the world - the majority of which are in Peru or Brazil, was in severe danger from illegal logging in Peru.

He accused the Peruvian loggers of committing a "monumental crime" against the natural world and providing "further testimony to the complete irrationality with which we, the 'civilised' ones, treat the world".

Survival International, a UK-based organisation supporting tribal people's rights, said tribes across the world were in "grave danger" of being forced off their land, being killed or decimated by disease.

"These pictures are further evidence that uncontacted tribes really do exist," said its director Stephen Corry.

"The world needs to wake up to this, and ensure that their territory is protected in accordance with international law. Otherwise, they will soon be made extinct."

The Brazilian government has published photographs of an isolated community of indigenous people living in the Amazon rainforest. It is the first time the world has seen this tribe and the first time for the tribe to see the outside world. Brazil’s National Indian Foundation (NIF) put the photos on its web site on May 29th. The foundation is a government agency that looks after the interests of the country’s disappearing tribes. José Carlos dos Reis Meirelles, an NIF official, said the photographs were taken over several weeks in April and May. He explained: “We did the flights to show their houses, to show they are there, to show they exist.” He is worried that the tribes-people will catch diseases they have never experienced before, such as influenza. There are also concerns that the spread of illegal logging will destroy their ancient way of life.

The newly-found tribe is surely one of the last remaining peoples on Earth never to have had contact with modern life. The name of the tribe and its exact location are being kept a secret. The only information released so far is that the tribe lives in a remote part of the rainforest near the Brazil-Peru border. The photographs that were taken show painted men dressed in warrior costumes with bows and arrows. They were trying to shoot down the photographer’s plane as it flew past. Another shot shows villagers standing in front of their primitive thatched huts. Survival International, a group that fights for the rights of indigenous people, warned the group and its unique culture is “in grave danger” of disappearing. It said: "The world needs to wake up…and ensure that their territory is protected…Otherwise, they will soon be made extinct."