Thousands of farmers took to the streets in northern Peru against US mining behemoth Newmont, which plans to build a controversial $4.8 billion gold and copper mine.
The protesters on Monday marched toward El Perol lake, among the water sources they depend to drink and farm, fear could be ruined by the massive Conga project in Cajamarca department.
"We are more than 5,000 farmers marching to the lake to stop the Conga project from destroying it," protest leader Milton Sanchez, head of a federation of local non-governmental groups, told AFP.
The government has boosted police presence to over 1,200 in the area.
But "we are not going to give in to police provocations," Sanchez said.
"What we are trying to do is defend and keep the lake, so that is why we will be camping at the site indefinitely."
Last week, Newmont said the project only will go forward in a socially and environmentally responsible way.
"The company is implementing significant efforts not only to recover credibility in Cajamarca, but also to increase the level of understanding and social acceptance of the Conga Project," it said in a statement.
The open-pit project, located some 3,700 meters (12,140 feet) above sea level, involves moving the water from four lakes high in the Andes mountains into reservoirs the company would build.
Local discontent and violence came to a boiling point last year, when at least five people were killed and many more injured during clashes against the Conga project.
More than 1,000 people participated in the protests and were met by police firing tear gas and wielding batons, as the government declared a state of emergency and mobilized security forces.
The Conga project was approved in 2010 by then-president Alan Garcia's government. His successor Ollanta Humala has also voiced support for the project, while insisting on environmental safeguards.