Peru's government has dispatched troops to a violence-wracked southern coastal valley where protests against a copper mining project have claimed the lives of two civilians and a police officer.

Defense Minister Jakke Valakivi told reporters Sunday that the 500 troops sent to reinforce 2,000 police would guard strategic locations including bridges and gas stations.

Two civilians have been killed by police bullets since protests began in late March against the $1.4 billion Tia Maria project of Mexican-owned Southern Peru Copper. On Saturday, a police officer died. His skull had been fractured by a rock.

Farmers fear the project would contaminate their crops. The owners say it would use desalinated water and pump water used in processing into the Pacific Ocean.

Mining provides 62 percent of Peru's export revenues.