A massive earthquake and tsunamis killed 350 people in one Chilean coastal town, doubling the total death toll on Sunday as the government tried to get aid to hungry survivors and halt looting.

President Michelle Bachelet said at least 708 people had been killed and called for calm as people desperate for food and water looted stores in some areas worst hit by Saturday's 8.8-magnitude quake, one of the world's biggest in a century.

Television images showed houses washed away by swirling waters, cars tossed into shattered buildings and boats lifted into the streets in coastal towns including Pelluhue and Constitucion, where 350 deaths alone were reported.

"It's an enormous catastrophe ... there's a growing number of missing people," Bachelet said, adding that food and medical aid was being sent to help the roughly 2 million people affected by the quake.

The quake wrecked hundreds of thousands of homes, mangled highways and bridges and dealt a heavy blow to infrastructure in the world's No. 1 copper producer and one of Latin America's most stable economies.

Giant waves set off by the quake crashed hundred of meters into some coastal towns and villages near the epicenter, demolishing houses and sending residents fleeing into the hills. The government had told Chileans immediately after the quake that there was no danger of a tsunami, an error it said was based on incorrect data from navy experts.

"I've got nothing left but what I'm wearing. We ran desperately up the hill and watched how the sea washed everything away," an unidentified woman from the fishing village of Duao told state television.

A lack of water, food and fuel sharpened the hardship for the hundreds of thousands of people left homeless, and widespread disruption to the power supply threatened to hamper Chilean industry's recovery.

Chile's biggest copper mines affected by the quake slowly resumed operations on Sunday despite limited power supplies, which analysts say could curtail exports.

In the hard-hit city of Concepcion, about 310 miles south of Santiago, about 60 people were feared to have been crushed to death in a collapsed apartment block where rescuers worked through the night to find survivors.

The government imposed a night-time curfew in Concepcion and the Maule region in a bid to stop looting and army troops began to arrive in the city late on Sunday.

Police used tear gas and water cannons to disperse a crowd of looters carrying off food and electrical appliances from one supermarket in Concepcion. Television images showed people stuffing groceries and other goods into shopping trolleys.

"People have gone days without eating," said Orlando Salazar, one of the looters at the supermarket. "The only option is to come here and get stuff for ourselves."

Concepcion's mayor, Jacqueline van Rysselberghe, said the situation was getting "out of control" due to shortages of basic supplies and called for troops to be sent to the city.

Aftershocks

The quake poses a daunting reconstruction challenge for President-elect Sebastian Pinera, who takes office in two weeks.

Crushed cars, fallen power lines and rubble from wrecked buildings littered the streets of Concepcion, which has about 670,000 inhabitants and lies 70 miles southwest of the quake's epicenter.

A string of strong aftershocks have rocked the country and thousands of Concepcion residents camped out in tents or makeshift shelters, fearing fresh tremors could topple weakened buildings.

Some economists predicted a deep impact on Chile's economy after the quake damaged its industrial and agricultural sectors in the worst-hit regions, possibly putting pressure on its currency.

The economic damage from the quake could be up to $30 billion, equivalent to about 15 percent of Chile's gross domestic product, said Eqecat, a firm that helps insurers model catastrophe risks.

Chile's fourth-largest copper mine El Teniente, which accounts for more than 7 percent of national output, resumed operations on Sunday. The nearby Andina mine was also due to resume operations but analysts feared power outages could still curtail supplies.

Production also resumed on Sunday at the Anglo-American Los Bronces copper mine, one of the company's two mines where power outages halted output, a union leader told Reuters.

Santiago's airport started to receive international flights for the first time since the quake struck. Officials said the runways were unscathed but the terminal building was damaged.

The temblor triggered tsunamis as far afield as Japan and Russia, but there were no immediate reports of injuries or serious damage.

(Additional reporting by Simon Gardner and Alonso Soto in Santiago and London bureau; Writing by Stuart Grudgings and Helen Popper, editing by Anthony Boadle)