About 600 extra troops will be posted to Pisco
Hundreds of extra soldiers have been ordered into areas of Peru devastated by Wednesday's massive earthquake to stem the rise in looting and unrest.
President Alan Garcia, who is touring the affected Ica region, called for order to be restored whatever the cost.
Some residents have begun to arm themselves to protect their property, while others have taken to the streets to protest at food and water shortages.
The 8.0-magnitude tremor left at least 500 people dead and thousands homeless.
The Ica region, south of the capital Lima, was devastated by the quake.
In Pisco, one of the region's worst-affected cities, rescuers said 127 bodies had been recovered from a church whose roof collapsed on top of the congregation.
A funeral service was being held at the San Clemente church when it was destroyed. The priest was rescued from the wreckage on Friday.
Officials have said they do not expect to find any more survivors from the disaster.
Fears over prisoners
There is growing unrest in and around Pisco, with aid vehicles and shops being looted.
Pisco resident Reyno Macedo, a 60-year-old mother of seven, said the people were desperate for supplies.
"The supply trucks go by and the anguish of watching them pass without giving us anything forces us to stop them and take what we need," she told Reuters.
Further south, in Ica, police fired shots into the air to disperse looters.
Residents of the city have begun arming themselves with iron bars to protect their possessions.
But the BBC's Dan Collyns in Pisco says there are now signs that distribution is picking up momentum.
There is now a strong presence of international aid agencies and more than 1,100 metric tons of donated aid from neighbouring Latin American countries and the Red Cross.
There are major concerns about the spread of diseases with hundreds of people sleeping out in the open. Clouds of dust swept up by the earthquake and the intensely cold nights have prompted fears that respiratory infections could spread.
And in the city of Chincha, near Pisco, authorities were still trying to trace about 600 offenders - reportedly including rapists and murderers - who escaped from jail during the quake.
Our correspondent says the prisoner issue is increasing fear and anxiety across the affected area.
President Garcia said 1,000 extra troops would be sent to the region - 600 to Pisco, 400 to the surrounding areas - to help hundreds of police officers and soldiers already there.
He said it was "natural" that "people who have been so recently fearing death suddenly have another fear - the fear of not having a litre of water tomorrow, or food".
But he added: "My obligation is to establish order in the country, and we're going to do that today, whatever it takes."
Aid agencies say as many as 80% of the people in quake-hit urban areas may not have access to clean water.
Dominic Nutt, working in the country for Save the Children, said many rural communities still have not been reached to assess the damage.
"The situation is probably worse than first imagined," he told the Associated Press.
Thousands of people remain on the streets of Pisco in spite of the cold weather - either because their homes have been destroyed or because they are too scared to return while the aftershocks continue.
Countries across Latin America - including Ecuador, Bolivia, Brazil, Mexico, Venezuela, Colombia and Chile - have sent relief supplies.
The US, Canada, Spain, Italy and France have also provided aid.
The earthquake happened in one of the most seismically active regions of the world.
In 1970, a 7.9-magnitude earthquake high in the Peruvian Andes triggered a landslide that buried the town of Yungay and killed 66,000 people.
EARTHQUAKE DISASTER ZONE, AND TECTONIC PLATES
Earthquake struck on Wednesday at 1841 local time
The 8.0-magnitude earthquake was centred just off the coast of Peru
Two tectonic plates clash at this region, the Nazca plate and the South American plate
There is about 7-8cm (3in) movement between the plates a year
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