- 50,000 troops for the rescue and recovery efforts
- Emergencies at nuclear reactors as cooling fails
- 200 to 300 bodies found in one coastal city after tsunami
- At least 90 fires in northeast Japan
- More than 100 aftershocks
Japan launched a massive, military-led rescue operation Saturday after a giant quake and tsunami killed hundreds of people and turned the northeastern coast into a swampy wasteland as authorities braced for a possible meltdown at a nuclear reactor.
Prime Minister Naoto Kan said he is sending 50,000 troops for the rescue and recovery efforts following Friday's 8.9-magnitude quake that unleashed one of the greatest disasters Japan has witnessed — a 23-foot (7-meter) tsunami that washed far inland over fields, smashing towns, airports and highways in its way.
The official death toll stood at 413, while 784 people were missing and 1,128 injured. In addition, police said between 200 and 300 bodies were found along the coast in Sendai, the biggest city in the area near the quake's epicenter. An untold number of bodies were also believed to be lying in the rubble and debris. Rescue workers had yet to reach the hardest-hit areas.
"Unfortunately, we must be prepared for the number to rise greatly," Chief Cabinet Secretary Yukio Edano told reporters Saturday.
Japanese media quoted local officials as saying the death toll was expected to top 1,000 as authorities tried to reach the hardest-hit areas.
More than 215,000 people were living in 1,350 temporary shelters in five prefectures, or states, the national police agency said. Since the quake, more than 1 million households have not had water, mostly concentrated in northeast.
Kan said a total of 190 military planes and 25 ships have been sent to the area.
"Most of houses along the coastline were washed away, and fire broke out there," he said after inspecting the quake area in a helicopter. "I realized the extremely serious damage the tsunami caused."
Adding to the worries was the damage at the Fukushima Daiichi nuclear power plant, where two reactors had lost cooling ability.
Aerial scenes of the town of Ofunato showed homes and warehouses in ruins. Sludge and high water spread over acres of land, with people seeking refuge on roofs of partially submerged buildings. At one school, a large white "SOS" had been spelled out in English.
The earthquake that struck off the northeastern shore ranked as the fifth-largest earthquake in the world since 1900 and was nearly 8,000 times stronger than one that devastated Christchurch, New Zealand, last month, scientists said.
Edano said an initial assessment found "enormous damage."
Police said 200-300 bodies were found along the coast in Sendai, the biggest city in the area. Authorities said they weren't able to reach the area because of damage to the roads.
For more than two terrifying, seemingly endless minutes Friday afternoon, the quake shook apart homes and buildings, cracked open highways and unnerved even those who have learned to live with swaying skyscrapers. Then came the devastating tsunami that washed far inland over fields and smashed towns.
The town of Rikuzentakada, population 24,700, in northern Iwate prefecture, looked largely submerged in muddy water, with hardly a trace of houses or buildings of any kind.
The entire Pacific had been put on alert — including coastal areas of South America, Canada and Alaska — but waves there were not as bad as expected.
Residents in Miyagi prefecture, who spent the night on top of a building, were rescued Saturday morning, the Asahi Shimbun newspaper reported.
"I was unable stay on my feet because of the violent shaking," a woman with a baby on her back told television in northern Japan. "The aftershocks gave us no reprieve, then the tsunami came when we tried to run for cover."
In one of the worst-hit residential areas, people buried under rubble could be heard calling out "Help" and "When are we going to be rescued?", the Kyodo news agency reported hours after the quake and tsunami. Rescuers were having a hard time reaching areas due to destroyed roads.
TV footage showed fires engulfing a large waterfront area in northeastern Japan. Houses and other buildings caught fire across large swathes of land in Kesennuma, near Sendai.
Kyodo reported that contact was lost with four trains along the northeast coast.
In one town alone on the northeastern coast, Minami-soma, some 1,800 houses were destroyed or badly ravaged, a Defense Ministry spokeswoman said.
A second, magnitude 6.6 quake struck central Japan along the northwest coast around 4 a.m. local time on Saturday, causing buildings to sway.Interactive: Japan earthquake aftershocks (on this page)
Japan declared states of emergency for five nuclear reactors at two power plants near Onahama after the units lost cooling ability when the power went out.
The government ordered residents near one of the plants to evacuate because reactor cooling systems failed and pressure inside was rising.
The Defense Ministry dispatched dozens of troops trained to deal with chemical disaster to the plant in case of a radiation leak.
An American working at the plant said the whole building shook and debris fell from the ceiling when the quake hit. Danny Eudy and his colleagues escaped the building just as the tsunami hit, his wife told The Associated Press.
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"He walked through so much glass that his feet were cut. It slowed him down," said Janie Eudy, who spoke to her husband by phone after the quake.
The group watched homes and vehicles be carried away in the wave and found their hotel mostly swept away when they finally reached it.
A second, nearby nuclear plant also reported cooling trouble.Video: Emergency declared at nuclear plant (on this page)
Overall, dozens of cities and villages along a 1,300-mile stretch of coastline were shaken by the quake and dozens of aftershocks that reached as far away as Tokyo.
"The earthquake has caused major damage in broad areas in northern Japan," Kan said at a news conference.
Even for a country used to earthquakes, this one was of horrific proportions because of the tsunami that crashed ashore, swallowing everything in its path as it surged several miles inland before retreating. The apocalyptic images resembled scenes from a Hollywood disaster movie.
Large fishing boats and other sea vessels rode high waves into cities, slamming against overpasses or scraping under them and snapping power lines along the way. Upturned and partially submerged vehicles were seen bobbing in the water. Ships anchored in ports crashed against each other.
Homes were washed away in the city of Sukagawa when an irrigation dam broke.
A ship with about 80 dock workers was swept away from a shipyard. All on the ship were believed to be safe , although the vessel had sprung a leak and was taking on some water, Japan's coast guard said.
The highways to the worst-hit coastal areas were severely damaged and communications, including telephone lines, were snapped.
Train services in northeastern Japan and in Tokyo, which normally serve 10 million people a day, were also suspended. Tokyo's Narita airport was closed indefinitely.Map: Quake details, historic comparisons (on this page)
In downtown Tokyo, large buildings shook violently and workers poured into the street for safety. The tremor bent the upper tip of the iconic Tokyo Tower, a 1,093-foot steel structure inspired by the Eiffel Tower in Paris.
Tens of thousands of people remained stranded in Tokyo as night fell and temperatures hovered just above freezing. The streets were jammed with cars, buses and trucks trying to get out.
Mobile phone lines were crammed, preventing nearly all calls and text messages. Unable to rely on their mobile phones, people formed lines at Tokyo's normally vacant public phone booths dotting the city.
The city set up 33 shelters in city hall, on university campuses and in government offices, but many planned to spend the night at 24-hour cafes, hotels and offices.
Austrian Lukas Schlatter saw houses and cars moving when the quake struck, and it was even hard for him to stand, “like I was a little bit drunk.”
Schlatter, a 22-year-old intern at the Austrian embassy in Tokyo, said there was a lot of shaking and books fell off shelves.“My Japanese co-workers were also scared because they said they had not experienced that strong of an earthquake in a long time,” he told msnbc.com.
More than 4 million customers at one point lost power in Tokyo and its suburbs, the NHK news agency said.
Around Sendai, waves of muddy waters flowed over farmland, carrying buildings, some on fire, inland as cars attempted to drive away. Sendai airport was inundated with cars, trucks, buses and thick mud deposited over its runways.
The tsunami roared over embankments, washing anything in its path inland before reversing directions and carrying the cars, homes and other debris out to sea. Flames shot from some of the houses, probably because of burst gas pipes.
A large fire erupted at an oil refinery in Ichihara city and burned out of control with 100-foot-high flames whipping into the sky.
Seventh strongest quake on record
The U.S. Geological Survey said the first quake hit at 2:46 p.m. local time on Friday and was a magnitude 8.9, the biggest earthquake to hit Japan since officials began keeping records in the late 1800s.
USGS files show it was also the fifth strongest worldwide since 1900 and the seventh strongest on record.
The quake struck at a depth of six miles, about 80 miles off the eastern coast, the agency said. The area is 240 miles northeast of Tokyo.
Japan's worst previous quake was in 1923 in Kanto, an 8.3-magnitude temblor that killed 143,000 people. A 7.2-magnitude quake in Kobe city in 1995 killed 6,400 people.
Japan has prided itself on its speedy tsunami warning system, which has been upgraded several times since its inception in 1952, including after a 7.8 magnitude quake triggered a 90-foot wave before a warning was given.
The country has also built countless breakwaters and floodgates to protect ports and coastal areas, although experts said they might not have been enough to prevent disasters such as the one that struck on Friday.
Japan lies on the "Ring of Fire" — an arc of earthquake and volcanic zones stretching around the Pacific where about 90 percent of the world's quakes occur, including the one that triggered the Dec. 26, 2004, Indian Ocean tsunami that killed an estimated 230,000 people in 12 nations. A magnitude-8.8 temblor that shook central Chile last February also generated a tsunami and killed 524 people.
The Associated Press and Reuters contributed to this report.