"Japan's most powerful earthquake since records began has struck the north-east coast, triggering a massive tsunami.
Cars, ships and buildings were swept away by a wall of water after the 8.9-magnitude tremor, which struck about 400km (250 miles) north-east of Tokyo.
A state of emergency has been declared at a nuclear power plant, where pressure has exceeded normal levels.
Officials say 350 people are dead and about 500 missing, but it is feared the final death toll will be much higher.
In one ward alone in Sendai, a port city in Miyagi prefecture, 200 to 300 bodies were found.
In the centre of Tokyo many people are spending the night in their offices. But thousands, perhaps millions, chose to walk home. Train services were suspended.
Even after the most violent earthquake anyone could remember the crowds were orderly and calm. The devastation is further to the north, along the Pacific coast.
There a tsunami triggered by the quake reached 10km (six miles) inland in places carrying houses, buildings, boats and cars with it. In the city of Sendai the police found up to 300 bodies in a single ward. Outside the city in a built-up area a fire blazed across several kilometres.
Japan's ground self-defence forces have been deployed, and the government has asked the US military based in the country for help. The scale of destruction from the biggest quake ever recorded in Japan will become clear only at first light.
The quake was the fifth-largest in the world since 1900 and nearly 8,000 times stronger than the one which devastated Christchurch, New Zealand, last month, said scientists.
Thousands of people living near the Fukushima nuclear power plant have been ordered to evacuate.
Japanese nuclear officials said pressure inside a boiling water reactor at the plant was running much higher than normal after the cooling system failed.
Officials said they might need to deliberately release some radioactive steam to relieve pressure, but that there would be no health risk.
US Secretary of State Hillary Clinton had earlier said the US Air Force had flown emergency coolant to the site.
But US officials later said no coolant had been handed over because the Japanese had decided to handle the situation themselves.
The UN's nuclear agency said four nuclear power plants had shut down safely.
Measured at 8.9 by the US Geological Survey, it struck at 1446 local time (0546 GMT) at a depth of about 24km.
The tsunami rolled across the Pacific at 800km/h (500mph) - as fast as a jetliner - before hitting Hawaii and the US West Coast, but there were no reports of major damage from those regions."
Tokyohive is posting more information here on which people have confirmed their safety.
There is a rumor going around that pop cellist Wakeshima Kanon is missing, and I for one hope that isn't the case. SO NOT THE CASE--SHE'S OKAY!!! And so is Berryz Kobo, which is super lucky because they were very near Sendai getting ready for a concert at the time.
Peace be with everyone.