1051 GMT: The United Nations says it is ready to send search and rescue teams to quake-hit Japan if the Asian state needs help, AFP reports from Geneva.
"Thirty-five international search and rescue teams are on alert, they are monitoring the situation and ready to help should Japan request aid," said Elisabeth Byrs, spokeswoman of the UN Office for the Coordination of Humanitarian Affairs (OCHA).
"The UN stands ready to help," she added.
1050 GMT: The death toll from the massive 8.9-magnitude earthquake that has hit off northeast Japan -- unleashing huge tsunamis along its Pacific coast -- has reached 32, including three in Tokyo, AFP reports from the Japanese capital citing press reports.
The figure could not be immediately confirmed by the Metropolitan Police Agency or the Tokyo Fire Department.
Among the dead are a 67-year-old man crushed by a wall and an elderly woman killed by a fallen roof, both in the wider Tokyo area, press reports said.
Three were crushed to death when their houses collapsed in Ibaraki prefecture, northeast of Tokyo.
Police in Iwate prefecture, near the epicentre, confirmed the deaths of 10 people there.
The National Police Agency, charged with compiling nationwide data on natural disasters, could not immediately confirm the figures.
"The damage is so enormous that it will take us much time to gather data," an official at the agency said.
1040 GMT: Marshall Islands disaster management officials have downgraded an earlier tsunami alert to a "tsunami watch" after the massive quake off northeast Japan, AFP reports from the capital Majuro.
"There is no danger as far as we are concerned," said government radio station manager Antari Elbon after receiving notification from officials that the danger of a tsunami had passed.
1038 GMT: New Zealand civil defence officials have issued a tsunami warning for the country and warned people to stay clear of beaches following a massive earthquake in Japan, AFP reports from the capital Wellington.
1030 GMT: Four nuclear power plants closest to a massive 8.9 magnitude earthquake in Japan have been safely shut down, the UN atomic watchdog says.
The International Atomic Energy Agency's Incident and Emergency Centre "received information from the International Seismic Safety Centre (ISSC) at around 0815 CET (0715 GMT) this morning about the earthquake of magnitude 8.9 near the east coast of Honshu, Japan," the watchdog said in a statement.
1025 GMT: A schoolboy was swept away in Miyagi prefecture -- the region on the northeast coast of Japan's main Honshu island worst hit by the tsunami -- by surging waters and there were fears the toll would keep climbing from the more than two dozen reported dead so far, AFP reports from Tokyo.
The masses of water overwhelmed coastal defences and swallowed up many square kilometres (square miles) of land in the region in scenes reminiscent of the devastation triggered by the 2004 Indian Ocean tsunami.
"I've never seen anything like this," said Ken Hoshi, a local government official in Ishinomaki, a Pacific port city in Miyagi prefecture.
"The water came as far as to the train station," hundreds of metres (yards) away from the coast, the 41-year-old official said as his city turned into a flood zone.
1020 GMT: A fire has broke out in the turbine building of Onagawa nuclear plant in Miyagi Prefecture -- on Japan's main Honshu island -- on Friday, AFP in Tokyo cites Kyodo News as reporting, following the huge 8.9 magnitude earthquake that struck at 14:46 pm local time (0546 GMT).
1010 GMT: Taiwan's central weather bureau says minor tsunamis set off by a massive quake in Japan reached Taiwan's coastline without causing any damage, AFP reports from Taipei.
0958 GMT: Belly-up ships, twisted cars and debris from shattered buildings crashed through the streets of port towns on the east coast of Japan's Honshu island on Friday, swept by a tsunami triggered by a huge earthquake which struck off the northeast coast of Japan at 14:46 pm local time (0546 GMT).
A muddy river filled with rubble -- some of it on fire and belching smoke -- raced across rice fields and through towns near Sendai in Miyagi prefecture, aerial television footage from one of the worst-hit areas showed.
A schoolboy was swept away there by the deadly waters and there were grave fears the toll would keep climbing sharply from the more than two dozen reported dead as a cold night settled over Japan.
The huge wall of sea water unleashed by Japan's worst quake on record hit the Pacific coast of Honshu island, sweeping away whole houses and turning harbour areas into scenes of utter devastation.
0950 GMT: The death toll from the massive 8.9-magnitude earthquake that hit off northeast Japan on Friday, unleashing huge tsunamis along its Pacific coast, has reached 26, AFP reports from Tokyo citing press reports.
Among the dead are a 67-year-old man crushed by a wall and an elderly woman killed by a fallen roof, both in the wider Tokyo area, press reports said.
0930 GMT: This is Nick Morrison in London taking over the live report from my colleagues in Hong Kong on the huge 8.9-magnitude earthquake that quake that struck off the northeast coast of Japan's main Honshu island at 14:46 pm local time (0546 GMT) Friday.
Stay with us for all the latest updates from our correspondents in Tokyo and in neighbouring countries on the aftermath of the quake as tsunami alerts are triggered across the region.
0906 GMT: Japan's National Police Agency, charged with compiling nationwide data on natural disasters, says it cannot confirm the death toll, with one official saying the "damage is so enormous that it will take us much time to gather data."
0902 GMT: Japanese media reports the death toll has risen to 19. Russian officials say the first tsunami waves have reached reached the Kuril Islands chain, with waves at Shikotan Island reaching one metre (3.3 feet) and waves at Kunashir Island 95 centimeters.
0850 GMT: The Philippine government has strongly urged residents of its Pacific coast to "go farther inland" amid a tsunami threat following a huge earthquake off Japan, AFP repots from Manila.
0845 GMT: Japan warns of imminent strong quake on northeastern Honshu island, AFP reports from Tokyo.
0840 GMT: Japanese press reports say at least eight people have been killed including a 67-year-old man crushed by a wall and an elderly woman killed by a fallen roof, both in the wider Tokyo area. Three were crushed to death when their houses collapsed in Ibaraki prefecture northeast of Tokyo.
0835 GMT: Hawaii is scrambling to evacuate locals and tourists from the coastline after the massive earthquake off Japan triggered a tsunami alert, officials on the Pacific island state said.
0828 GMT: Hawaii orders evacuations after tsunami alert, AFP reports from Honolulu.
0822 GMT: Strong aftershock felt in Tokyo, AFP reports from the Japanese capital.
0821 GMT: Beijing residents report feeling the Japan quake, AFP reports from China's capital.
Workers in some office towers in the Chinese capital, more than 2,500 kilometres (1,500 miles) from the quake epicentre, reported via chat sites that they had clearly felt the tremor.
However, no injuries or damage were immediately reported in China.
0817 GMT: Japanese PM says no nuclear plant radiation has been detected, AFP reports..
0809 GMT: Japanese government says 'tremendous damage' from quake, AFP reports from Tokyo.
0805 GMT: Hawaii issues tsunami warning, braces for waves, AFP reports from Honolulu.
0804 GMT: The Mariana Islands are on tsunami alert and evacuating citizens after a huge earthquake off Japan, the Pacific state's Emergency Management Office (EMO) said, according to AFP reports from the island's main city Saipan.
0800 GMT: Here is a recap of the main events surrounding the huge earthquake that has struck off Japan's northeast coast:
- A massive 8.9-magnitude earthquake hits Japan at 14:46 pm (0546 GMT), unleashing a monster 10-metre high tsunami that sent ships crashing into the shore and carried cars through the streets of coastal towns.
- Many injuries were reported from Pacific coastal areas of the main Honshu island and the capital Tokyo, police said, while TV footage showed widespread flooding in the area. One person was confirmed dead.
- Helicopter footage showed massive inundation in northern coastal towns, where floods of black water sent shipping containers, cars and debris crashing through towns.
- Mud waves were shown racing upstream along the Natori river in Sendai city, blanketing farm fields.
- In the capital, where millions evacuated strongly swaying buildings, multiple injuries were reported when the roof of a hall collapsed during a graduation ceremony, police said.
- Plumes of smoke rose from at least 10 locations in city, where four million homes suffered power outages. Port areas were flooded, including the carpark of Tokyo Disneyland.
- The US tsunami monitoring center widens a warning to virtually the entire Pacific coast, including Australia and South America, after a massive earthquake in Japan.
