The miner, owned by Chinese firm MMG Ltd, said in a statement late on Monday the convoy had been moving through a mining area near the city of Espinar in the Cusco region when the vehicles were intercepted and stoned. Two were torched.

Peru is the world's No. 2 copper producer and its economy relies heavily on exports of the red metal, especially to top buyer China. The Andean country's economy has been one of worst affected in the region by the coronavirus outbreak.

The protesters "are violently demanding an economic benefit that is not linked to Minera Las Bambas, and that has caused riots in the area," Las Bambas said.

"They sprayed gasoline on the vehicles and proceeded to set them on fire. The drivers of both units, who were threatened by the protesters, suffered personal injury and are currently in a safe place, being treated to verify their state of health."

Las Bambas produces some 400,000 tons of copper per year, or about 2% of global extraction of the metal.

Communities near Espinar protested last week against the Antapaccay copper miner, controlled by Glencore, and on Monday blocked sections of a mining corridor in the area, non-governmental organization Mining Conflict Observatory reported.

The public ombudsman's office said the protesters' demands, outlined by Espinar social organizations, centered on calls for a so-called "solidarity" payment from Antapaccay of 1,000 soles ($285) for each adult in the area.

An Antapaccay spokesman said the miner had a cooperation agreement with Espinar since 2003, but that the payment sought by the protesters did not respond to the aims of that plan.

"Instead we have proposed launching 30 infrastructure projects for up to some 30 million soles ($8.59 million) to generate large-scale employment, a microcredit program without interest for small businesses and direct food assistance for the population most affected by the pandemic," he said.

The protest has not hit Antapaccay's operation, the spokesman added.

($1 = 3.4937 soles)

By Marco Aquino