THREE people were killed and 17 injured when police in Peru opened fire on a protest at a copper mine on Monday.

The demonstration by local farmers was against plans for the construction of a £4.9 billion Chinese-run processing plant at the Las Bambas mine in Cotabambas.

Front for Defence of the Interests of Cotabambas (FDIC) leader Jaime Osorio said the violence broke out when police attacked the rally of 15,000 people with tear gas.

But Interior Minister Jose Luis Perez said that police were forced to respond when demonstrators trespassed on mine property and threw stones at officers.

President Ollanta Humala said that he regretted the loss of lives but appealed to protest leaders for calm, adding that Las Bambas was Peru’s most important mining project.

The plant is scheduled to open in 2016 and produce 400,000 tonnes of copper per year.

Copper accounts for 60 per cent of Peru’s export earnings.