Riot police clash with protesters in Peru (VIDEO)
There were no reports of injuries or arrests during the breakout of violence.
The protests against Peru's largest gold mining project have dragged on for months now. Last December, the government imposed emergency rule in the region in an effort to lower tensions.
Most of the protesters are ordinary farmers who say the mining project will destroy four local lakes, a crucial source of water in the region.
The work on the $4.8 billion Minas Conga copper and gold project had been stalled by the earlier protests, but on June 19 mining company Minera Yanacocha announced it would resume the work after it carries out required improvements.