Rio de Janeiro: In a rare move, Brazil is providing armed back-up to indigenous people protecting the world's most threatened tribe from illegal loggers, a decision that campaigners lauded as a "landmark" in efforts to halt deforestation in the Amazon.

Officials moved in to the Brazilian rainforest after a group of from the Guajajara tribe, who call themselves The Guardians of the Amazon, seized a logging gang and burnt their truck, rights group Survival International said.

A soldier stands guard in front of a truck loaded with logs that were illegally cut from the Amazon rain forest. Credit:AP/File

"Over the weekend, a team of Ibama [Brazil's environmental protection agency] and environmental military police arrived in response to The Guardians' call for help," said Sarah Shenker, a senior campaigner with Survival.