Brazil’s indigenous affairs department (Funai) has accused an American missionary of exposing an isolated indigenous tribe to disease and possibly death.

Steve Campbell, a Christian missionary, entered the area occupied by the Hi-Merimã tribe last month, one of the few dozen tribes in Brazil that has had no contact with the outside world.

“It’s a case of rights violation and exposure to risk of death to isolated indigenous population,” a Funai spokesman said in a written statement to Thomson Reuters Foundation.

“Even if direct contact has not occurred, the probability of transmission of diseases to the isolated is high.”

Experts have warned that there is an increasing likelihood of missionaries trying to contact isolated tribes in Brazil after the country’s new president, Jair Bolsonaro, appointed an evangelical preacher as the new minister in charge of indigenous affairs.

During his campaign, Bolsonaro pledged to open up protected land and demarcate “not one centimeter” for indigenous people or quilombolas – descendants of runaway slaves.

Campbell camped in the area the Hi-Merimã occupy and invaded one of the isolated tribe’s recently abandoned camping grounds, Funai said.

Attempts to reach Campbell were unsuccessful.

Little is known about the Hi-Merimã, who live in the state of Amazonas.

They became known for rejecting contact with the outside world and maintaining hostile relations even with other indigenous communities.

Details about what kind of penalties Campbell may face are not clear, as Funai has not yet notified federal prosecutors or the police. The government agency said it will notify them this week.

According to reports from Brazilian newspaper Folha de São Paulo, Campbell claimed to have entered the area by mistake, while teaching Indians from the neighbouring Jamamadi tribe to use a GPS device.

Campbell has been living among the Jamamadi for years, but received no authorisation to do so, according to Funai.

About two months ago another American Christian missionary was killed after trying to contact an isolated tribe on an island in the Bay of Bengal.