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 quake, which struck about 400km (250 miles) north-east of Tokyo. A state of emergency has been declared at a nuclear power plant but officials said there were no radiation leaks.
The death toll is unclear, but police say 200 to 300 bodies have been found in the port city of Sendai.At least 133 other people are reported by Kyodo news agency to have died, many more are unaccounted for.
Measured at 8.9 by the US Geological Survey, the tremor struck at 1446 local time (0546 GMT) at a depth of about 24km.
The first waves from the tsunami have reached the US mainland at Oregon, and people have been evacuated from coastal areas of that state and in California and Washington.
Some of the biggest waves of between 6-7ft (about 2m) would hit near California's Crescent City, predicted the US National Weather Service.
The waves earlier passed Hawaii, but there were no reports of major damage.
A tsunami warning was extended across the Pacific to North and South America, where many other coastal regions were evacuated, but the alert has since been lifted in most parts, including the Philippines, Australia, China and Indonesia.
Strong waves hit Japan's Miyagi and Fukushima prefectures, officials said, damaging dozens of coastal communities.
Kyodo said a 10-metre wave struck Sendai, which is in Miyagi.
Japan's NHK television showed a massive surge of debris-filled water sweeping away houses, cars and ships and reaching far inland.
Motorists could be seen trying to speed away from the wall of water.
Farmland around Sendai was submerged and the waves pushed cars across the runway of the city's airport. Fires broke out in the city's centre.
In other developments:
- A passenger train was missing in Miyagi prefecture, and a ship carrying 100 people was swept away, police told Japanese media
- Fire is engulfing swathes of coastland, including homes and buildings, at Kesennuma city in Miyagi prefecture
- A major explosion hit a petrochemical plant in Sendai; further south a huge blaze swept through an oil refinery in Ichihara city, Chiba prefecture
- Some 1,800 homes are reported destroyed in the city of Minamisoma, Fukushima prefecture
- A dam burst in north-eastern Fukushima prefecture, sweeping away homes, Kyodo news agency reports
- There were reports of about 20 people injured in Tokyo after the roof of a hall collapsed on to a graduation ceremony
Nearly 3,000 people have been ordered to evacuate from near the Fukushima power plant, where a state of emergency has been declared. The cooling system failed in one of its reactors when it shut down automatically because of the earthquake.
Prime Minister Naoto Kan said no radiation leaks at that power plant or any of the other reactors in the quake-hit zone had been detected.
In a televised address, he extended his sympathy to the victims of the disaster and said an emergency response headquarters had been set up.
The UN's nuclear agency said four nuclear power plants had shut down safely.
In Iwate prefecture, also near the epicentre, an official said it was difficult to gauge the extent of the destruction.
"Roads were badly damaged and cut off as the tsunami washed away debris, cars and many other things," said Hiroshi Sato, a disaster management official in Iwate.
Residents and workers in Tokyo rushed out of apartment buildings and office blocks and gathered in parks and open spaces as aftershocks continued to hit.Many people in the Japanese capital said they had never felt such a powerful earthquake.
In central Tokyo, a number of office workers are spending the night in their offices because the lifts have stopped working.
"This is the kind of earthquake that hits once every 100 years," said restaurant worker Akira Tanaka.
Train services have been suspended and millions of commuters were stranded in the Japanese capital.
About four million homes in and around Tokyo suffered power cuts.