PUERTO MALDONADO, Peru — In this sweltering Amazonian city, Pope Francis on Friday gave a stirring defense of the region’s indigenous people, whose lands and way of life are threatened by industry and government, leaving almost no institutions to protect them.

It was a departure from an otherwise purely religious visit to Peru, where Francis arrived on Thursday from Chile, but it fit squarely within his advocacy for environmental preservation.

Facing a crowded sports arena — where the main stage was neatly divided between clerics sitting on chairs and indigenous people in traditional garments sitting on the ground — Francis said he understood the local challenges.

He deplored, on one hand, “the pressure being exerted by great business interests that want to lay hands on its petroleum, gas, lumber, gold and forms of agro-industrial monocultivation” and, on the other hand, threats from policies that ostensibly aim to conserve land “without taking into account” its inhabitants.