LIMA, Peru — The head of a Chinese-owned mining concern says as many as 20 armed men attacked an exploration camp in northern Peru, killing two security guards and burning down the facility.

General Manager Wu Jian of Rio Blanco Copper says a miner and another guard are also missing.

Rio Blanco is a subsidiary of Zijin Mining Group Co.

The operation has been a source of conflict in the region.

Some local residents oppose it for fear of contamination and depleted water supplies.

Human rights groups accuse police and private guards of torturing protesters at the camp in 2005.

Wu says he does not believe that mining opponents were responsible for Sunday's attack.

Interior Minister Octavio Salazar said Monday that police are investigating.

- AP