© Reuters//Enrique Castro-MendivilAndean people protest against Newmont Mining's Conga gold project during a march near the Cortada lagoon at Peru's region of Cajamarca, November 24, 2011.
President Ollanta Humala declared a 60-day state of emergency Sunday in a northern region torn by more than a week of protests against a highlands gold mine, the country's biggest investment, by peasants who fear for their water supply.

The emergency restricts civil liberties such as the right to assembly and allows arrests without warrants in four provinces of Cajamarca state that have been paralyzed for 11 days by increasingly violent protests against the $4.8-billion Conga gold and copper mining project. U.S.-based Newmont Mining Corp. is the project's majority owner.

Dozens have been injured in clashes between police and protesters, some of whom have vandalized Conga property.

Humala said in a brief televised address Sunday night that protest leaders had shown no interest "in reaching minimal agreements to permit a return of social peace" after a day of talks in Cajamarca with Cabinet chief Salmon Lerner and three other ministers.

Humala said the government "has exhausted all paths to establish dialogue as a point of departure to resolve the conflict democratically" and blamed "the intransigence of a sector of local and regional leaders."

He said the emergency would take effect at midnight Sunday.

Lerner's group was accompanied by Peru's military and police chiefs and guarded by hundreds of heavily armed police.

Local elected officials in Cajamarca, including the state's governor, have led protests against Conga, an extension of the nearby Yanacocha mine, for more than a month.

They say they fear it will taint and diminish water supplies affecting thousands and have demanded a new study of the environmental impact of the mine, which was scheduled to begin production in 2015.

Several weeks ago, the Interior Ministry asked prosecutors to file criminal charges against Cajamarca Gov. Gregorio Santos and four other local leaders who have led protests against Conga, a top ministry lawyer, Julio Talledo, told The Associated Press.

The charges include "hindering the functioning of public services" and carry prison terms of at least two years. It was not immediately clear whether prosecutors have acted on them.

Newmont announced last week that it was suspending work at Conga until order could be restored.

Government officials have expressed no intention of redoing Conga's environmental impact study, which was approved by the Ministry of Mining in October 2010.

Those plans call for displacing four lakes more than two miles high and replacing them with reservoirs. Local residents say they fear that could affect an important acquifer on which thousands depend.

Humala told Cajamarca during campaign swings before his June election that clean water was more important for him than gold. Many local inhabitants said they now feel betrayed by the president.

Peru's economy depends heavily on mining, which accounts for 61 percent of its export income.

Humala, a former radical leftist who moved toward the center before being elected this year, agreed to a tax on windfall profits in the industry that the government says will yield about $1 billion a year to help fund social programs.