Two million people have been affected by the massive earthquake that struck central Chile on Saturday, President Michelle Bachelet has said.
In a TV address, she said the forces of nature were testing the nation.
So far at least 300 people have been confirmed killed in the earthquake that struck in the early hours of Saturday.
The 8.8 quake - one of the biggest ever - triggered a tsunami that has been sweeping across the Pacific, although waves were not as high as predicted.
Japan is still on high alert, with scores of thousands of people urged to evacuated areas at risk.
Ms Bachelet said the forces of nature had "once again put to the test our ability to deal with adversity and get back on our feet. And we are examining every way to restore all the basic services in the country. But there's still a lot to do".
AT THE SCENE
Gideon Long, BBC News, Santiago
The streets of the capital, usually buzzing with activity on a summer weekend like this, are eerily quiet and dark. Nearly 24 hours after the quake struck, whole swathes of the city have no electricity and no running water.
Many people have packed up and left to stay with friends and relatives who are better off than they are.
The city's new buildings seemed to have survived more or less intact. But it's the old buildings that suffered. I drove past my local church - still intact but missing its dome, which crashed to the ground when the earth began to shake.
Around the city of Concepcion, whole villages have been flattened. Highways have been sliced in two and bridges have collapsed.
But help is arriving. Chile has a long history of earthquakes and the authorities here know how to deal with them.
Ms Bachelet said she had declared a state of catastrophe in six regions.
Chile is vulnerable to earthquakes, being situated on the Pacific "Ring of Fire" where the Pacific and South American plates meet.
The earthquake struck at 0634 GMT, 115km (70 miles) north-east of the city of Concepcion and 325km south-west of the capital Santiago at a depth of about 35km. It is the biggest to hit Chile in 50 years.
Widespread damage to roads and buildings has been reported in many areas, including the capital where a chemical plant caught fire.
Electricity, water and phone lines have been cut.
At least 85 people died in the region of Maule alone, journalists there reported.
Many deaths were also reported in the regions of Santiago, O'Higgins, Biobio, Araucania and Valparaiso.
TV pictures showed a major bridge at Concepcion had collapsed into the Biobio river.
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