A Venezuelan indigenous leader who was an opponent of armed groups and illegal mining has been shot dead in the Amazonas state capital, a non-governmental organization and three people with knowledge of the case said.

Virgilio Trujillo Arana, a 38-year-old indigenous Uwottuja man, was a defender of the Venezuelan Amazon and had set up community groups to act as guardians of the Autana municipality of Amazonas.

Trujillo was shot in the head three times by a gunman who fled to a waiting vehicle in Thursday’s attack in the city of Puerto Ayacucho. He had reportedly received threats relating to his work.

“In life, Trujillo Arana strongly opposed the presence of foreign groups and illegal mining exploitation in the indigenous territories of the Uwottuja people, in the Alto Guayapo area,” indigenous rights NGO AC Kape Kape wrote on Twitter.

The Uwottuja community is made up of about 15,000 people.

Non-governmental organizations and a United Nations report have denounced the presence of violent criminal groups that control gold mines in the jungle.

The ministry of communication and information and the prosecutor’s office did not immediately respond to a request for comment.

Communities from the town of Uwottuja announced last February their decision to defend their territory against a “silent invasion” by criminal groups, rejecting illegal mining exploitation as well as the use of their land for illicit activities.

Mining has been prohibited since 1989 in Venezuela’s southern Amazonas state, which is not part of the so-called Arco Minero, or Mining Arc, a gold exploitation zone 111,000 sq km created by decree in 2016 by the government of President Nicolas Maduro.

The office of United Nations high commissioner for human rights Michelle Bachelet has asked the government to regularize mining activities and guarantee that they are carried out under international and environmental standards.