CONCEPCION, Chile - (AP) - Rescuers found signs of life in aquake-toppled building on Monday as the world offered aid tovictims of a catastrophe that killed more than 700 people. Troopsand police cracking down on looters arrested dozens of people forviolating a curfew.

"We are confronting an emergency without parallel in Chile'shistory," Bachelet declared Sunday, a day after the magnitude-8.8quake - one of the biggest in centuries - killed at least 708people and destroyed or badly damaged 500,000 homes.

Some coastal towns were almost obliterated, first shaken by thequake, then slammed by a tsunami that lifted whole houses andcarried them inland and that reduced others to piles of sticks.

Across the highway from a looted supermarket in Concepcion, thebig city closest to the epicenter, rescuers heard the knock oftrapped victims inside a toppled 70-unit apartment building beganto drill holes through thick walls trying to reach them, said firedepartment Commander Juan Carlos Subercaseux.

Firefighters had already pulled 25 survivors from the building,as well as eight people who died.

Only the chop of military helicopters flying overhead broke thesilence demanded by rescuers straining to hear signs of life withinthe building.

Police chief Eliecer Soler said officers arrested 55 people forviolating a curfew imposed after looters sacked nearly market intown. Troops ordered into the city by Bachelet began to patrol toenforce security.

At least a few looters re-emerged to rob a market on Mondaydespite Bachelet's order placing the city's security under militarycommand.

On Sunday, ingenious looters used long tubes of bamboo andplastic to siphon gasoline from underground tanks at a closedgasoline station.

Eduardo Aundez, a Spanish professor, watched with disgust as asoldier patiently waited for looters to rummage through a downtownstore, then lobbed two tear gas canisters into the rubble to getthem out.

"I feel abandoned" by authorities, he said. "We believe thegovernment didn't take the necessary measures in time, and nowsupplies of food and water are going to be much more complicated."

The U.N. said Monday that it would begin rushing aid deliveriesto Chile following Bachelet's announcement she was seekinginternational aid.