Peru declared a state of emergency late Friday in the country's south, where a violent protest against the Tia Maria copper mine has killed four people in two months.
The move, which means the military will take charge of security in the province of Islay, came hours after a clash between protesters and police left a 55-year-old demonstrator dead, according to medical sources.
Witnesses said the victim died after he was shot in the chest. Local authorities did not confirm or deny the information.
Additionally, four demonstrators and three police were injured when a group of protesters tried to take control of a local police station.
Earlier this month, the government had already deployed some troops to help local police maintain order.
Protesters are demonstrating against the project by Mexican-owned copper firm Southern Peru, which they say will pollute their water and damage agriculture.
Local residents, who have opposed the project for years, have been protesting since March 23.
The mining company last week called for calm, proposing a two-month break to address doubts about the mining project.
Peru, which has significant mineral wealth, is the second largest copper producer and the fifth largest gold producer in the world.