Following Saturday's devastating earthquake that hit Chile, authorities have imposed a curfew near the epicenter after widespread looting of supermarkets.
The 8.8 magnitude earthquake was one of the most intense ever measured, and the official death toll has risen to 711. Chilean President Michelle Bachelet has declared a "state of catastrophe" in central Chile, calling the quake a disaster of unthinkable magnitude.
The government deployed 10,000 troops to control the looting, according to the Associated Press. In some of the worst-hit areas, authorities used tear gas and water cannons to manage the crowd. In some cases the tear gas disrupted efforts to search for survivors.
Bachelet, who leaves office March 11, has ordered major supermarkets to give away essential supplies.
More than half a million homes were destroyed and the government says an estimated 2 million people are living on the streets.
"It shook very violently for about three or four minutes … all of my neighbors were running to the hills," Christopher Daniel Morgan, who was in Chile at the time of the earthquake, told "Good Morning America."
"The main destruction that there was in the central part of Concepcion ... buildings have toppled and entire houses were down and also there were bridges that have completely fallen," Morgan said.
Some coastal towns suffered a deadly double blow as the quake triggered giant waves that crashed into the coastline, carrying with them cars, boats and houses. In one coastal village, the death toll was 350.
"The tsunami destroyed almost everything on the seafront [and] the center of the town was completely destroyed. This means lots of people still haven't been accounted for," Constitucion Mayor Hugo Tilleria told state television, according to the AP.
Scientists said Saturday's earthquake was 500 times stronger than the quake that hit Haiti in January. But the recovery effort in Chile is likely to go easier because the country is better prepared -- with stronger infrastructure, stronger building codes and a more effective government. Chile is one of the most developed countries in Latin America and has a lot of experience with earthquakes.
The strongest earthquake ever measured -- a 9.5 magnitude -- struck Chile in 1960. Ever since, the country has required that new buildings be built with earthquakes in mind.
So far, no Americans have been confirmed among the dead. However, with communications in Chile still spotty, approximately 3,000 of about 18,000 Americans believed to be in the country have not been in contact with U.S. officials since the earthquake, according to the State Department.
"We are facing a catastrophe of such magnitude that has caused damages that will require gigantic efforts from every sector of our country -- both private and public sector," Bachelet told the media Sunday, according to an ABC News translation. "We face an emergency without precedent in the history of Chile in which we need fast and urgent answers.
Aftershocks Continued to Shake the Region.
Fearing that roofs or walls still could crash over them, or because they had no homes to return to, many people in Chile spent the first full night after the earthquake outdoors, ignoring government instructions to stay indoors if homes looked secure.
"They're afraid to go back in their homes, as anyone would be with aftershocks," said Tracy Reines, international response director of the American Red Cross. "The Chilean Red Cross has about 30 to 40 local Red Cross branches in the area, so they do everything from first aid to food, [and] soon will be emergency shelter and the like."
Helicopter footage early Sunday showed damage to highways, entire neighborhoods leveled and other areas flooded.
Rescue Effort in a Toppled Apartment Building
In the southwest coastal city of Concepcion -- the second-largest city in Chile with a population of 670,000 -- extensive damage included a newly opened 15-story apartment that toppled backward, trapping an estimated 60 people inside, the AP reported. Rescuers only managed to free 16 in the first 24 hours after the earthquake, and continued to work with two power saws and an electric hammer on a generator that was running out of fuel.
"It's very difficult working in the dark with aftershocks, and inside it's complicated," Paulo Klein, who was leading a group of rescue specialists from Puerto Montt, Chile, told the AP. "The apartments are totally destroyed. You have to work with great caution."
Gas and power lines snapped in the city, starting a fire at the local university, according to the AP.
Looting broke out in Concepcion by Sunday morning.
"I think the most critical need is probably the restoration of electricity and water in certain parts of the country," ABC News' Melia Patria reported from Santiago. "When people don't have electricity and water, I think that's where we're seeing a lot more looting because people are restless and they need resources."
Police used water cannons and tear gas to scatter people who forced open the doors of the Lider supermarket in Concepcion, the AP reported.
The government is working with power companies to restore disrupted electrical supplies, Bachelet said, adding that she is asking the private sector to pitch in on other emergency matters, too.
"In coordination with the largest supermarket chains, I have disposed the free distribution, in the regions of Maule, Bio Bio and some sectors of Araucania, of all products of main necessity that are stored in their facilities so they can be given away in a coordinated, orderly [manner] and in the places authorities decide and communicate to the citizens," Bachelet said.
"Also," she said, "in the next few hours we are expecting to normalize commercial air traffic, both nationally and internationally."
The Red Cross announced Saturday that it had raised at least $50,000 for aid to the earthquake-ravaged country. To learn more about how you can donate, visit www.redcross.org.
"We have received multiple offerings of international support and we have opened several lines and we have already mentioned that we'll have a global perspective on this to know what we were going to request in terms of international aid," Bachelet said. "Chile is a country that can resolve some of these issues itself, but there are other areas where we are going to receive support."
Bachelet said those areas likely would include emergency field hospitals, mobile bridges, communication systems, electrical systems and possibly rescue teams and water purification systems.
U.S. officials said there have been no requests for U.S. aid yet, though the United States can provide "helos for evacuations, satellite communications, imagery and some supplies all at working levels."
The Christian humanitarian organization, World Vision, began distributing "hundreds of blankets and some water containers to Santiago's earthquake survivors over the weekend," according to a press statement released by the charity.
"We are extremely concerned about the emotional impact of so many aftershocks on children. Not only the physical needs, but the psychosocial needs of children in the quake zone will be a priority once the full extent of the needs are known and we can begin delivering much-needed supplies," said Tatiana Benavides, World Vision's national director in Chile.
American Embassy Workers Safe After Chile Earhquake
Paul Simons, the U.S. ambassador to Chile, told "Good Morning America" Sunday that all American employees at the U.S. Embassy have been located.
"We have no reports of any [American] fatalities or serious injuries," Simons said.
However, he added that that, as of this morning, the embassy had no reports from Concepcion.
The earthquake, which hit just after 3 a.m. local time Saturday, was stronger but much deeper than last month's Haitian earthquake, likely making the number of casualties far fewer than those in the Caribbean nation.
The Chile earthquake struck 22 miles below the surface in the Bio Bio region of the country, while the Haiti earthquake struck only 6 miles below the surface, according to scientists with the U.S. Geological Survey.
The three-minute quake struck less than 100 miles north of Concepcion but caused damage as far away as the capital, Santiago, nearly 200 miles away.
In the hours after Chile's quake, coastal cities from Japan to Australia were placed on alert for a tsunami. Most areas were spared widespread destruction from the waves, though at least five deaths and 11 people missing were reported on Robinson Crusoe Island off Chile, according to the AP.
Ronald Scott, an American who was staying at a hostel in Santiago when the earthquake hit, told ABC News that while he was terrified, the damage he witnessed was far less extensive than what he saw reported from Haiti.
"It was very scary," Scott said. "The first thing I did was jump underneath the first table I could find and even that was about to collapse on me.
"Everything just started jumping up and down, the lights went out and everything sounded like a railroad train," he said. "The buildings were shaking, but they're still standing because of the construction."
Massive Earthquake, Modest Tsunami
The buildings in Chile are constructed specifically to withstand earthquakes, and the country is no stranger to disaster from an unexpected quake.
"Since 1973 they've had 13 earthquakes over 7.7 magnitude," said Paul Earle, a seismologist from the U.S. Geological Survey.
Chile has the record for the world's strongest recorded earthquake -- a 9.5 magnitude quake that struck in 1960.
That earthquake sent a tsunami to Hawaii that killed 61 people and destroyed 500 homes. Tsunami waves triggered by an earthquake can travel at the speed of a jet before slamming into a distant coast as unusually high waves.
This time, Hawaiian officials cleared beaches and sounded alarms for hours before the expected arrival of the tsunami.
But scientists with the Pacific Tsunami Center said the islands "dodged a bullet." Hawaii's tsunami waves, which hit around 1 p.m. Hawaii time, were relatively mild and did not cause any damage.
To read all of ABC's coverage on the Chile Earthquake, click here.
ABC News' Michael S. James, Kate McCarthy, Kirit Radia, ABC News Radio and the Associated Press contributed to this report.