RIO DE JANEIRO (AP) — Illegal loggers ambushed a group of indigenous forest guards in Brazil's Amazon, killing one and injuring another, authorities said Saturday.

A logger also died in the attack Friday night in Maranhao, a northeastern state, according to FUNAI, a state agency that represents indigenous interests.

Paulo Paulino Guajajara, who died after being shot in the face, was a leader in a group seeking to protect the Arariboia indigenous reserve from incursions.

Federal police will investigate Guajajara's killing in order to "bring those responsible for this crime to justice," said Sergio Moro, the justice and public security minister.

An indigenous leader in the area said the forest guards had previously received threats and wore protective vests while on patrol.

"We informed federal agencies of the threats but they didn't take any action," leader Sonia Guajajara said.

Some indigenous groups in the Amazon rainforest say they are increasingly vulnerable to incursions by loggers and cattle ranchers. Fires used to clear land in the Amazon increased sharply in July and August, causing international alarm over a region seen as critical to curbing climate change.

Concern about the rainforest had heightened after Brazilian President Jair Bolsonaro took office this year with calls to loosen protections for nature reserves and indigenous lands.

Bolsonaro says some economic development is necessary in the Amazon.