Peruvians trying to take control of an Amazon oil drilling installation clashed with police, leaving at least 20 injured and 40 arrested, local media reports said.
The protest in the village of Pichanaki in central Peru came on the second day of a strike in protest at oil operations that local people fear will contaminate rivers and soil.
The injured were hurt by tear gas fired by police, although one report said a person was hit by a bullet.
The attempted raid came as local authorities began talks with government officials seeking a solution to their demands.
Local people want the government of President Ollanta Humala to live up to what they say is a campaign promise to stop oil exploration in the Amazon.
Pichanaki is cut off because buses are honoring the strike and blocking the only road into the town.
The government in Lima called for an end to any violence.
It said a meeting to inform the people of Pichanaki will be held February 17.
The oil is being drilled by the company Pluspetrol. Since January it has been the target of protests by other Amazon indigenous communities seeking indemnization for what they believe is environmental damage.