The confirmed death toll from Tuesday's magnitude-6.3 quake centered near Christchurch, New Zealand, rose to 75, and officials said it was almost sure to climb further. Some 300 people were listed as missing.
"There are bodies littering the streets, they are trapped in cars, crushed under rubble and where they are clearly deceased our focus ... has turned to the living," police Superintendent Russell Gibson told the Associated Press.
Prime Minister John Key said at a news conference that 75 people were confirmed to have been killed, with 55 of them identified. He declared a state of national emergency, giving the government wider powers to take control of a rescue and recovery operation that was growing by the hour.
Rescuers are concentrating on at least a dozen buildings that collapsed or were badly damaged.
Former U.S. Sen. Evan Bayh and his wife Susan, were in Christchurch during the earthquake but were not injured.
"I kept thinking I was in the middle of a movie, and that I was going to wake up and realize it had all been a dream, but unfortunately sometimes these things are true," said Bayh. "You're walking along, and the ground shakes and all of a sudden a building next to you is collapsing. Nothing in life really prepares you for that.
Susan Bayh was in the center of the city shopping near Cathedral Square, while her husband was at a lunch at a university when the quake hit.
"This nice German man took me by my coat and threw me out into the street," Susan Bayh said. "What was really frightening is what was happening ... on the streets as well as inside the buildings. ... There was a lady next to me, probably maybe a yard away that had a piece of concrete the size of maybe a half of a twin size bed on her upper half and you could just see her feet."
The couple reunited hours later after Bayh estimated he'd walked 9 to 10 miles trying to reunite with his wife after learning she'd been uninjured.
"There were aftershocks every 15 to 20 minutes, and so just when you thought maybe things had calmed down another one would hit and parts of buildings would be falling off, so you never really felt quite safe," said Bayh.
Aftershocks have sent survivors scrambling for safety in Christchurch, the nation's second largest city. Amid darkness, rain and falling temperatures, rescue and recovery efforts are under way.
Olivia Carville, a reporter in Christchurch said the immediate aftermath was devastating.
"Bodies were just lying on pavements covered in towels because there were no sheets and no way to get the bodies out of the city," said Carville. "It was one of the most terrifying experiences I will ever have in my life and the city just looked like a war zone."
Thousands of people in the city moved into temporary shelters at schools and community halls. Others, including tourists who had abandoned their hotels, huddled in hastily pitched tents and under plastic sheeting as drizzling rain fell, while the Red Cross tried to find them accommodation.
Parker said 300 people were listed as missing but cautioned that they did not know the number trapped in collapsed buildings, according to the Associated Press. More than 400 rescue workers were joining the search, including teams from Australia, Singapore, Taiwan, the United States and Britain.
The earthquake caused 30 million tons of ice to fall from New Zealand's largest glacier, 120 miles from Christchurch. Twelve-foot-high waves swept up and down the lake for 30 minutes.
The two aftershocks -- one magnitude 5.6 and another 5.5 -- shook Christchurch within hours of the initial 6.3 earthquake.
The aftermath caused buildings to crumble, including the 130-year-old Christchurch Cathedral. Its spire toppled onto the city square. Afteshocks continued through the night, some with a magnitude of 5.
"To see the top of the cathedral come down, I've never seen anything like it," one survivor said. "There's just no words to be quite honest. It was just absolutely awful."
Phone service has been crippled, and 80 percent of the city has no electricity or water.
"This is much, much more serious than last time," said Roger Sutton, CEO of the power company Orion New Zealand, according to the New Zealand Herald. "We have some major power assets that have been damaged by this quake."
People have been urged to conserve water; not to shower, take baths or flush toilets. Temporary relief shelters have been set up. One in nearby Hagley Park was full and has turned people away. More than 2,500 people have shown up at the Ellerslie Flower Show, a scheduled event in Christchurch.
The tents for the show were being used as an overnight shelter for people. The show's organizers provided 1,500 meals, according to New Zealand's News Channel 3.
Google launched a person-finder application on its website to aid those looking for missing people. The website allows anyone to enter information about someone's whereabouts, which can then be viewed by the public. Similar sites were launched during the disasters in Haiti and Chile.
Houses have been devoured by mud, and the sides of buildings have been sheared off. Buildings have collapsed and bricks have scattered onto the streets. Roads and sidewalks have buckled, and water has gushed through giant cracks in the pavement.
Deputy Prime Minister Bill English reported that 350 military personnel were in Christchurch providing first aid, security and search and rescue services, and 250 others were preparing to relieve them. More military, police and search and rescue teams were expected to arrive overnight.
Scene on the Ground: Chaos
On the ground, chaos abounded. Residents were crying and screaming, and more than 100 people, including a dozen Japanese students, were still thought to be trapped in the rubble.
"There are about 10 people from my work in there," one woman said, standing outside her damaged office building.
Rescue workers battled debris and flooding to free those trapped in an office building in the city center.
"I was buried under part of the ceiling," one woman said.
"I think if we'd been at the end of the building. We would have all been squashed," another survivor said.
One man was lowered by rope to safety from a high-rise building.
"Stairwells, completely gone, 17 stories with just both stairs gone," another survivor said.
With such extensive damage, Prime Minister Key reassured residents that help from the United States and Australia was on the way.
"It's an absolute tragedy for this city, for New Zealand, for the people we care so much about," Key said.
"We may well be witnessing New Zealand's darkest day," he said.
Key described a scene of "utter devastation" and vowed to work as fast as possible.
"This is a community that is absolutely in agony," Key said. "We will get through this. New Zealand will regroup and Christchurch will regroup."
Click here to see photos of the earthquake's aftermath.
The Earthquake's Magnitude was 6.3
The 6.3 magnitude quake struck at 12:51 p.m. Tuesday local time, and was very shallow in depth, measuring 2.5 miles beneath the surface, causing violent shaking, and widespread damage.
"The building just exploded," resident Barry Saunders said in an interview with Radio New Zealand. "It was just like a movie. It took three or four seconds to comprehend what was going on."
The U.S. Geological Survey said today's quake was centered three miles from the city.
This latest tremor came five months after a 7.1 magnitude earthquake struck the city of 350,000.
That quake in September caused no deaths but badly damaged buildings throughout the city, many of them the same structures that collapsed today.
Christchurch Mayor Bob Parker declared a state of emergency shortly after the quake hit, and ordered people to evacuate the city center. He said it was impossible to say how many people are still trapped in the rubble, but that it is estimated to be more than 100.
Troops were deployed to help victims trapped amid the rubble, the airport was closed, and the Christchurch Hospital briefly evacuated before it was deemed safe for patients to return.
Some people were stuck in office towers, forcing firefighters to extend their ladders to rescue people trapped on roofs. Among the dead were passengers aboard two buses crushed by falling buildings.
New Zealand television showed residents walking amid the rubble in a daze, some badly injured from falling debris.
Newspaper editor Andrew Holden said he heard glass cracking and falling throughout the building, and clouds of dust billowing through the newsroom.
"The roof above the main staircase collapsed so there was a fair bit of rubble down the staircase," Holden said in an interview with Radio New Zealand. "We've had some good size shocks before but when you've got a quake of that size that just continues on and on."
ABC News Radio and The Associated Press contributed to this report.