Peruvian authorities have ordered China's Chinalco mining giant to partially halt its activities at a copper facility until it stops dumping waste.
Chinalco Mining Corporation controls the Toromocho Project in the center of the South American country, one of the largest pre-production copper plants in the world.
Friday's order by Peru's environmental protection agency OEFA was sparked by inspections carried out March 16-20 that detected contaminants in the Huacrococha and Huascacocha lakes.
The agency posted a video on its website showing a yellowish liquid flowing into the bodies of water.
Peru is the world's second biggest copper producer. Chinalco has been developing the Toromocho project since 2008.