Lima: Peru on Saturday instituted a 60-day state of emergency in a mineral-rich region roiled by deadly protests against Southern Copper Corp’s stalled $1.4 billion Tia Maria project.

The emergency state in nine districts in the southern region of Arequipa suspends civil liberties, allowing police and troops to enforce curfews and order an end to two months of protests that led Southern Copper to formally put the project on hold last week.

‘The national police with the backing of the armed forces will take charge of keeping public order,’ Prime Minister Pedro Cateriano said in a televised news conference late on Friday.

The announcement followed the death of a fourth person in clashes between protesters and police as Tia Maria opponents pushed for a definitive cancelation of the 120,000-tonnes-per-year proposed copper mine.

Opponents, mainly farmers, say they fear a new copper mine in the region will pollute land and water and hurt their crops.

Southern Copper, controlled by Grupo Mexico, has said it will use the highest standards and promised to build a desalinisation plant in its revised environmental plan, which was approved last year.