Peru's army has set up checkpoints and imposed curfews in the jungle state of Amazonas after clashes between police and indigenous protesters.
At least 22 police and nine protesters have died, officials say. Protesters say 30 indigenous Indians are dead.
The trouble began on Friday near Bagua with protesters angry at plans to drill for oil and gas on ancestral land.
They took 38 police officers hostage - at least nine were killed on Saturday as the army moved in to free them.
This is the worst violence in Peru since the end of the Shining Path insurgency in the 1990s and the biggest internal challenge faced by President Alan Garcia since he came to power in 2006, the BBC's Americas editor Emilio San Pedro says.
The curfew - from 1500 to 0600 (2000-1100 GMT) - took effect immediately, as the authorities announced they had made 72 arrests.
In a statement, President Garcia said Peru was suffering from "an aggression against democracy", and vowed to respond "with composure and firmness".
Due to the "irresponsible aggression" by the protesters, police officers "have been savagely and barbarically murdered", he said on Saturday.
The killers used "identical methods as those used by the Shining Path" guerrillas, said Garcia, who stated that "humble police that were surrendering unarmed" had their throats slit and were attacked with spears.
But protest leaders have vowed to keep on the pressure.
As the army moved in to secure the area, thousands of Indians with wooden spears said they would keep up blocking roads if government forces did not halt efforts to break up their demonstrations.
"We are fighting because we fear our land will be taken away," said Denis Tangoa, a protester at one blockade told Reuters news agency.
Fuel and transport blockades have disrupted Peru's Amazon region for almost two months.
The indigenous tribes want to force Congress to repeal new laws that encourage foreign mining in the rain forest.
"We are not going to give up until they reverse these laws that will damage us," Luis Huansi, a tribal leader told Reuters.
Critics says Mr Garcia made a huge error when he failed to take into account the native groups' opposition to exploitation of what they consider their ancestral territory, reports the BBC's Dan Collyns from the area.
All hopes for dialogue now seem a distant possibility, our correspondent says.