Hungry earthquake survivors ransacked a public market Friday, while other mobs looted a refrigerated trailer and blocked aid trucks, prompting Peru's president to appeal for calm. Aid finally arrived to the disaster zone after about 36 hours without much help.

With hopes diminishing of finding more survivors from Wednesday's devastating magnitude-8 quake, the death toll had reached at least 510. Another 1,500 people were injured, overwhelming the few hospitals in Peru's southern desert region.

Severe damage to the only highway to the hardest hit zone slowed trucks from Lima. But food, water, tents and blankets were finally arriving, and with Peruvian soldiers distributing aluminum caskets, the first mass funerals were being held.

• Click here for photos.

"Nobody is going to die of hunger or thirst," President Alan Garcia said following complaints that aid was not arriving fast enough for some 80,000 people who lost loved ones, homes and belongings in Wednesday's magnitude-8 temblor and the many aftershocks that have followed.

"I understand your desperation, your anxiety and some are taking advantage of the circumstances to take the property of others, take things from stores, thinking they're not going to receive help," Garcia said. "There is no reason to fall into exaggerated desperation knowing that the state is present."

Electricity, water and phone service remained down in much of southern Peru. Garcia predicted that "a situation approaching normality" in 10 days, but acknowledged that reconstruction would take far longer. That was obvious to everyone in the gritty port city of Pisco, where Brig. Maj. Jorge Vera, chief of the rescue operation, said 85 percent of the downtown was destroyed, a collection of rubble piles and half-collapsed hulks.

The relief effort showed signs of organization by mid-morning, with the military clearing rubble, police identifying corpses and civil defense teams ferrying food. Housing ministry officials assessed who will need new homes, and in several towns, survivors carrying big buckets lined up under an intense sun as soldiers delivered water from trucks.

At least 18 aftershocks of magnitude-5 or greater have struck since the first quake, and Peru's fire department said the death toll had risen to 510. Destruction was centered in Peru's southern desert, in the oasis city of Ica and in nearby Pisco, about 125 miles southeast of the capital.

Also damaged was the town of Chincha, where a prison wall fell down, and at least 571 prisoners escaped. Only 29 were recaptured, a top prisons official said.

Searchers still sought bodies and survivors Friday at the San Clemente church on Pisco's main square, where hundreds had gathered on the day Roman Catholics celebrate the Virgin Mary's rise into heaven for a memorial Mass for a man who died a month earlier. The church's domed ceiling broke apart in shaking that lasted for an agonizing two minutes.

About 50 bodies had been removed by dawn, said Jorge Molina, the search and rescue team leader, who still held out hope of finding more people alive. Three bodies still lay unclaimed in bags on the plaza, where rescue workers from Lima had pitched tents and relatives held vigil.

Other churches were severely damaged in nearby Ica, Guadalupe and Canete, their pews covered in tons of stone, timbers and dust. Elsewhere in Pisco, the five-story Embassy Hotel killed about 15 guests and workers when it accordioned onto its ground floor. As many as 20 others were believed still trapped in a billiard hall, and a dozen children who had been studying English at night were killed in school.

"Those who were in front managed to get out, but those in back died," said Manuel Medina, who dug out his nephew's body from the rubble of their classroom.

In the cemetery where burial vaults collapsed and crosses tumbled over, a man painted the names of the dead onto headstones. Some 200 headstones were lined up, and grieving relatives lowered a stream of coffins into shallow graves they dug themselves in the hard dirt.

"My dear child. Gloria!" wailed Julia Siguis, her hands spread over two small coffins. "Who am I going to call now? Who am I going to call?" Her cousin and niece had been buried by their collapsing home.

Doctors treated 169 injured and failed to save 30 people at Pisco's hospital, which was transferred to a basketball court on Thursday when officials decided to collect the dead inside. Dr. Jose Renteros, the physician in charge, said a third of the injured were airlifted to Lima with trauma, broken bones and head wounds.

Some survivors seemed in shock. Felipe Gutierrez, 82, sat in his pajamas — his only clothing — in front of what was his Pisco home. The quake reduced it to rubble and he, his 74-year-old wife, their two children and three grandchildren sat staring at the ruins, a tangle of adobe, straw and all of their belongings.

"Yesterday we slept on a mattress, and now we'll have to set up a tent, because we have no where to live," he said.

International help includes cash from the United States, United Nations, Red Cross and European Union as well as tents, water, medicine and other supplies.

The U.S. government released US$150,000 in emergency funds for emergency supplies and was sending in medical teams — one of which is already on the ground. It also sent two mobile clinics and loaned two helicopters to Peruvian authorities.

But the U.S. Navy hospital ship Comfort, now docked in Ecuador, won't make the three-day trip to Pisco because both governments decided it wasn't needed. The Comfort carries 800 medical personnel, but Peru needs supplies more than doctors, U.S. Embassy spokesman Dan Martinez said.

Magnitude 8 quakes are capable of causing tremendous damage. Scientists said this one was a "megathrust" — similar to the catastrophic Indian Ocean temblor in 2004 that generated deadly tsunami waves. "Megathrusts produce the largest earthquakes on the planet," USGS geophysicist Paul Earle said.

The temblor occurred in one of the most seismically active regions in the world, where the Nazca and South American tectonic plates meet. The plates are moving together at a rate of 3 inches a year, Earle said.