Angry employees from a local market took to the streets city of Piura, some 652 miles north of Lima, in what would end in a deadly clash.
The protesters threw glass bottles and rocks at police who responded with tear gas. Police arrested over 30 of the protesters.
Officers also shot their pistols into the air in attempt to scatter the mob, many of whom were trying to reach the market to sack goods.
Local reports said deaths were from gunshot wounds or blows from blunt objects.
The protests lasted into the night, with a violent element lighting bonfires and surrounding the police station.