(Recasts, updates death toll and adds quotes)

By Jean Luis Arce

PISCO, Peru, Aug 17 (Reuters) - Peruvians frustrated over slow emergency aid looted pharmacies and scuffled in food lines on Friday as rescuers picked through rubble for survivors two days after a massive earthquake killed at least 510 people.

The Pacific coast city of Pisco, one of the hardest hit by the quake, suffered so many deaths that families squabbled in a graveyard over spots to bury their dead.

With the death toll still rising from a magnitude 8.0 earthquake that struck south of the capital Lima on Wednesday evening, a powerful aftershock renewed panic on Friday and some people sprinted away from food lines in Pisco.

Gloria Diaz, 63, complained about sparse aid as she stood with dozens of people in line in front of a Pisco pastry shop.

"You think this is enough to live on?" she asked as she waited for a small sandwich with a group of her grandchildren.

People in dusty clothes, distraught after two nights without shelter, bemoaned a lack of medical attention and emergency supplies.

On the outskirts of Pisco, small groups blocked the road, stopping and looting aid trucks arriving from Lima.

President Alan Garcia visited the disaster area, promising food and water but also warning that the government would go after looters.

"The state protects but the state also maintains order," he said.

Countries throughout Latin America, as well as the United States and European nations, were sending or have pledged aid.

POOR AREAS HIT

Friday's strongest aftershock had a 5.9 magnitude and damaged homes in the impoverished region of Huancavelica, which also lies on the coast south of Lima.

Many victims of Wednesday's earthquake were poor, killed when their flimsy mud-brick homes collapsed. Hospitals and morgues were overwhelmed, forcing residents to lay bodies out on city streets.

Teams of volunteers were trying to help emergency crews find the living and treat the injured.

The rescue of a man from the rubble of a collapsed church brought some hope to search teams but others were pessimistic.

"I don't think there are any survivors," said Paul Cana, a 30-year-old miner on a rescue squad.

About 510 people have been confirmed dead and 1,000 wounded since the big quake, the United Nations said on Friday.

Peru's civil defense agency said 453 people died but an official said the toll may rise as the rubble was cleared and information trickled in from more remote areas.

"My feeling is that the number could rise," said Walter Tapia, an operations coordinator for the agency.

The towns of Nazca and Palpa that flank the Nazca Desert -- famous for gigantic images of animals carved into the barren earth thousands of years ago -- were hard to reach.

"We have other populations that were also affected from which we have recently begun to receive reports," Tapia said.

Thousands of people were left homeless by the quake and have been forced to sleep outside.

Pisco, renowned for the grape liquor that bears its name, was hit hard by the quake, along with the towns of Ica and Chincha, where hundreds of prisoners escaped from a jail when the tremor tore the old building apart.

The quake was one of the worst natural disasters to hit the South American country in the last century. In 1970, an earthquake killed an estimated 50,000 people in avalanches of ice and mud that buried the town of Yungay.

AlertNet news is provided by