Amazon Indians in Brazil who remain uncontacted by modern civilization react to an airplane flying over them earlier this month. Brazil's government this week agreed to release information about the tribe, one of the few still living in near-total isolation.

Rio de Janiero, Brazil ? Brazil’s government agreed to release stunning photos of Amazon Indians firing arrows at an airplane so that the world can better understand the threats facing one of the few tribes still living in near-total isolation from civilization, officials said Friday.

Anthropologists have known about the group for some 20 years but released the images now to call attention to fast-encroaching development near the Indians’ home in the dense jungles near Peru.

“We put the photos out because if things continue the way they are going, these people are going to disappear,” said Jose Carlos Meirelles, who coordinates government efforts to protect four “uncontacted” tribes for Brazil’s National Indian Foundation.

Shot in late April and early May, the foundation’s photos show about a dozen Indians, mostly naked and painted red, wielding bows and arrows outside six grass-thatched huts.

Meirelles told The Associated Press in a phone interview that anthropologists know next to nothing about the group, but suspect it is related to the Tano and Aruak tribes.

Brazil’s National Indian Foundation believes there may be as many as 68 “uncontacted” groups around Brazil, although only 24 have been officially confirmed.

Anthropologists say almost all of these tribes know about western civilization and have sporadic contact with prospectors, rubber tappers and loggers, but choose to turn their backs on civilization, usually because they have been attacked.

“It’s a choice they made to remain isolated or maintain only occasional contacts, but these tribes usually obtain some modern goods through trading with other Indians,” said Bernardo Beronde, an anthropologist who works in the region.

Brazilian officials once tried to contact such groups. Now they try to protectively isolate them.

The four tribes monitored by Meirelles include perhaps 500 people who roam over an area of about 1.6 million acres (630,000 hectares).

He said that over the 20 years he has been working in the area, the number of “malocas,” or grass-roofed huts, has doubled, suggesting that the policy of isolation is working and that populations are growing.

Remaining isolated, however, gets more complicated by the day.

Loggers are closing in on the Indians’ homeland – Brazil’s environmental protection agency said Friday it had shut down 28 illegal sawmills in Acre state, where these tribes are located. And logging on the Peruvian border has sent many Indians fleeing into Brazil, Meirelles said.

“On the Brazilian side we don’t have logging yet, but I’d like to emphasize the ‘yet,”‘ he said.