More than thirty hours after a magnitude-8.8 earthquake hit south-central Chile, the death toll has reached 708 on Sunday while rescue and relief efforts are underway.

Chilean President Michelle Bachelet told a news conference that the number of the killed is expected to increase further.

"The last number I have is 708," said Bachelet, adding that the country was facing "a catastrophe of such unthinkable magnitude" and would need enormous efforts to recover.

Among the dead, 541 people was in the Maule region, 64 in Bio Bio, and other 103 deaths were from other affected areas.

In the Maule region, more than 350 people died in the coastal town of Constitution after the megaquake and an ensuing tsunami.

Media reports also said around 400 people disappeared on Sunday morning after the huge waves of Orrego island, located at the outfall of the Maule river, hit Constitution.

Earlier, the president said over 2 million people out of the 16.6 millon Chileans were affected. Over 1.5 million buildings were demaged or destroyed.

Some estimates put the total damage at between 15 billion U.S. dollars and 30 billion U.S. dollars, equal to 10 percent to 20 percent of the country's gross domestic product.

In the hardest-hit town of Concepcion, 115 kilometers from the epicenter of the quake, which is off the coast of Maule region, the whole downtown area was razed to the ground.

Most of the 200,000 residents in the city stayed outdoor fearing aftershocks. They desperately need water, food, shelter and other living necessities.

The Chilean government has announced a series of measures for disaster relief.

Bachelet said food distribution would begin to help the affected people to stand up to the difficulties.

The president said the Maule region and the city of Concepcion are being placed under special rules to speed up the delivery of aid.

She added that Army officers would be coordinating with local officials to guarantee the security and speed up aid distribution.

The president also ordered deployment of 10,000 soldiers and police to the affected areas to guarantee the security and to collaborate on the aid delivery.

Bachelet urged the civil and military authorities, as well as the private sector "to collaborate on the different works that have to be done," because the reconstruction will take time and resources.

Temporary hospitals will be set up in the cities of Concepcion, Talca and Curico, which were the most damaged by the earthquake, she added.

However, in affected areas, massive damage to the infrastructure is hampering rescue efforts.

In Concepcion, 25 people were rescued from a collapsed building, but dozens of others were believed to have been trapped under rubble.

Officials said transportation is slowly back to normal.

The airport in Chilean capital of Santiago has reopened with a total of five international fights due to arrive on Sunday. One metro line in the city is now operating and roads are passable.

Unlike Haiti which was also struck by a huge quake recently, Chile said it can handle the relief efforts for the moment and hasn't asked for any external help.

In Washington, officials said U.S. Secretary of State Hillary Clinton intends to visit Chile on Tuesday as scheduled despite the killer quake.

An earthquake measuring 8.8 on the Richter scale hit southern Chile early Saturday, triggering tsunamis as well as communications and power breakup.

Dozens of countries had issued tsunami alerts, fearing the earthquake could cause a devastating tsunami across the Pacific. But on Sunday, that concern receded after no casualties have been reported in other countries other than Chile.

But frequent aftershocks still rock Chile, with more than 115 took place in the first 30 hours after the quake, including a 6.1-magnitude tremor.