A tsunami sparked by the strongest earthquake to hit Japan since records began devastated coastal areas yesterday and killed more than 300 people, with the death toll set to rise.
In scenes described by a television commentator as "looking like the end of the world", waves of up to 10 metres slammed into Japan's north-east, sweeping away buildings, ships and cars as though they were bathtub toys.
Japan's chief cabinet secretary, Yukio Edano, said: "Our initial assessment indicates that there has already been enormous damage. We will make maximum relief effort based on that assessment."
Evacuations from many coastal areas were ordered across the Pacific basin as residents braced themselves for heavy waves.
The quake struck at 2.46pm Tokyo time about 130 kilometres offshore east of Sendai, a one-million-strong coastal city in the north-east of Japan's main island of Honshu.
Police last night reported that between 200 and 300 bodies had been recovered from the city area, with a further 88 people dead and 349 missing.
The city's streets and airport were engulfed by floodwaters, while a fire was reported to have swept through one district.
A passenger train outside the city, with an unknown number of people aboard, was unaccounted for and a ship carrying 100 people was swept away, according to reports.
"I've never seen anything like this," said Ken Hoshi, a local government official in Ishinomaki, a port city in Miyagi prefecture, where Sendai is located, according to Agence France-Presse.
Television pictures taken from a helicopter showed water sweeping across farmland near the north-east coast, leaving a trail of devastation in its wake.
Other shocking images showed waves lifting and carrying away scores of vehicles in seconds, bringing large boats inland and leaving others lying on their sides as the waters laid waste to whole communities.
Motorists sped inland as they tried to avoid being caught. Many vehicles and parts of buildings washed away by the floodwaters were carried out to sea as the waves fell back.
Fires broke out at scores of locations, including in the turbine building of a nuclear power station, while another blaze engulfed an oil refinery near Tokyo, with natural gas tanks creating balls of flame that sent thick plumes of black smoke into the sky.
Thousands of people living close to a nuclear power plant in Fukushima prefecture were evacuated when operators were unable to cool the reactor, causing the government to declare a nuclear alert, although there were not believed to be any radiation leaks.
About 4.4 million homes in the north of the country were without power and industrial giants such as Sony, Nissan and Toyota closed factories yesterday as the earthquake alert sounded.
Transport services were heavily disrupted, with several airports, including Tokyo's Narita airport, shut down and bullet train services to and from affected regions suspended.
In the capital, workers fled onto the streets as the quake caused buildings to sway, even though the city is about 320 kilometres from the quake's epicentre.
Rachel Ferguson, a weather anchor for the NHK World TV channel, said she was at work when the building started gently swaying.
"But then it started to get more and more intense," said Ms Ferguson, 30, originally from Scotland, in an e-mail. "About 15 mins later there was a strong aftershock, almost as powerful as the first. We scrambled under the desks. After an hour, the ground was still swaying a little.
She said Tokyo was filled with a sense of unease, should another strong quake come. "Aftershocks have come every hour or so all day."
Many commuters were left stranded at their workplaces as the rapid transit system was shut down and roads choked with traffic, with the authorities using loudspeakers and television broadcasts to advise people against walking long distances home.
Eight military aeroplanes were sent to the affected coastal regions to survey the damage, while troops were also dispatched, joined by 900 rescuers as the embattled government of Naoto Kan called an emergency meeting to discuss measures to deal with the crisis.
The 8.9-magnitude earthquake, the seventh-largest ever recorded, was felt even 2,400km away in Beijing, and was followed by dozens of aftershocks, including one recorded at 7.1 magnitude.
Stock markets and the value of Japanese yen currency fell as the country's already stuttering finances faced another setback, with analysts predicting the government would be forced to inject funds into the economy to prevent a slump, increasing the national deficit. Initial assessments put the cost of the tsunami's damage at US$10 billion (Dh36.7bn).
France, the United States, China, the United Kingdom, the UAE and the United Nations were among those to offer assistance yesterday, with dozens of UN search-and-rescue teams on standby to help if Tokyo requested.
In total more than 15 countries around the Pacific basin issued tsunami warnings, although the alert was lifted in the first nation set to be hit, Taiwan, when large waves failed to materialise yesterday evening. Alerts for Australia and New Zealand were also lifted. However, early waves to hit Hawaii were recorded at one metre amid concern they could increase in size.
In 140 years of records, no other earthquake in Japan has reached the magnitude of the one that struck yesterday.
Yet the country has suffered multiple previous earthquakes, sitting as it does at the junction of several continental and oceanic plates.
Most recently, on Wednesday, a 7.3-magnitude quake shook northern parts of the country, although there were no casualties.
Among the worst seismic events in Japan's history are the 6.8-magnitude quake in 1995 that struck the city of Kobe, killing about 6,400 people, and most devastating of all in terms of loss of life, the 7.9-magnitude Great Kanto earthquake of 1923 that destroyed much of Tokyo Tokyo and resulted in 140,000 deaths.
The "Ring of Fire" arc of seismic vulnerability on which Japan lies was also responsible for the Indian Ocean tsunami of December 2004 in which 230,000 people died.
Japan is however regarded as one of the best-prepared nations in the world for dealing with the effects of seismic activity, with children drilled on how to respond to earthquakes even when they are in nursery.