Japanese nuclear officials have confirmed a hydrogen explosion has occurred at Unit 3 of Japan's stricken Fukushima Dai-ichi nuclear plant, similar to an earlier one at a different unit in the facility.
Another strong earthquake has struck off the coast of Japan.
The quake hit 150 kilometres north-east of Tokyo, shaking tall buildings in the capital.
Authorities did not issue a tsunami alert.
The Tokyo Electric Power Company says it has suspended the first round of planned rolling power outages that were scheduled from 6.20am (local time) today.
Actual electricity shortages in the wake of Friday's massive earthquake were not as severe as initially estimated, the company said.
Internet communications provider Skype say they have made the Skype Access service free to use over WiFi in Japan, helping users in public spaces like cafes and airports to easily get in touch with loved ones overseas.
"What are the odds of us being in two major earthquakes on two continents in about two weeks?"
Probably, about two million to one.
But that's what has happened to American band The Melvins.
Not only were they in Tokyo when the disastrous 8.9 earthquake hit Japan on Friday, they also experienced the 6.3 earthquake that shook up Christchurch less than a month ago.
The Los Angeles band had travelled to Japan for the final leg of their tour, which began in New Zealand. The Japan earthquake struck shortly before their last show in Tokyo.
According to frontman Buzz Osborne, the band was also at Christchurch airport when the quake hit on February 22.
The Bank of Japan has injected 7 trillion yen (NZ$100 billion) into money markets to ease concerns about possible negative impacts on banks and other financial institutions following the disaster, Kyodo News reports.
New Zealanders caught up in Japan's earthquake aftermath can now get help from Ministry of Foreign Affairs and Trade (Mfat) consular staff stationed at Narita international airport in Tokyo and in the northern city of Sendai.
No New Zealanders have been harmed in Japan's massive earthquake and subsequent tsunami which hit the country on Friday, the ministry said.
Tokyo shares plunged shortly after opening today as investors reacted to the biggest earthquake in Japan's history and the devastating tsunami that followed.
Shares fell 5.42 per cent as the key index sank below 10,000 to its lowest levels since November.
The Ministry of Foreign Affairs and Trade is advising Kiwis against all tourist and non-essential travel to Tokyo due to disruptions to essential services such as transport and electricity. They are also advising against travelling to earthquake and tsunami affected areas in the northeast.
Here's where you can get a free "Pray for Japan" PicBadge to add to your Facebook profile picture.
Here's a Q&A with scientists on the subject of the nuclear incident at Japan's earthquake-damaged Fukushima No1 plant.
The International Atomic Energy Agency says investigators in Japan found radiation levels have returned to normal at the Onagawa nuclear power plant, situated north of the troubled Fukushima plant.
The rolling power blackouts are about to get underway in Japan. The Tokyo Electric Power Co. said the blackouts, the first ever in Japan, will happen throughout today. The prefectures affected are Tokyo, Gunma, Tochigi, Ibaraki, Saitama, Chiba, Kanagawa, Yamanashi and the eastern half of Shizuoka. Each district will have the power cut off for about three hours at a time.
Prime Minister Naoto Kan has appealed to the public for cooperation.
CNBC anchor Larry Kudlow put his foot in it when he made an on-air statement about the earthquake in Japan.
Kudlow was listening to a report about the global stock markets doing well in the wake of the quake. "All in all, the market taking this in stride," his co-host said to him.
"The human toll here looks to be much worse than the economic toll and we can be grateful for that," Kudlow responded. "And the human toll is a tragedy, we know that."
He later apologised, saying he "mis-spoke".
There's been no change to Air New Zealand's schedule of flights to Japan, since the devastating earthquake there. The airline operates daily flights to Tokyo from Auckland.
Figure skating's world championships, due to begin on March 21 in Tokyo, may be cancelled, the International Skating Union said.
Officials now believe at least 10,000 people were killed in one area, Miyagi, alone following Friday's magnitude 9.0 earthquake and 10-metre high tsunami.
Kyodo news agency in Japan reported that there were more than 530,000 evacuees.
The wind over Japan's radiation-emitting nuclear power plant will be blowing from the south today, the Japan Meteorological Agency said, potentially affecting residents north of the facility.
More than 313,000 evacuees in northeastern Japan spent the night at around 1,850 evacuation centres at schools and other public institutions, NHK has reported.
They are facing extreme cold at night as the heating systems are short of fuel.
The Bank of Japan stood ready to prop up the financial system amid fears the Tokyo stock market will nosedive when trading opens Monday following the disasters that killed thousands and devastated the country's northeast.
Preliminary estimates put repair costs from the earthquake and tsunami in the tens of billions of dollars - a huge blow for an economy that lost its place as the world's No. 2 to China last year, and was already in a fragile state.
There have been at least 360 aftershocks east of Honshu since the magnitude 9 quake on Friday night, according to United States Geological Survey reports.
Japanese experts are stressing there are no signs of a critical meltdown at the Fukushima nuclear power plant and a Chernobyl-like disaster is not on the cards.
"I think the worst scenario has been avoided," said Hiromi Ogawa, a former engineer who managed Toshiba Corporation's nuclear power generation project, told Japan Times.
Ogawa said seawater injected into the Fukushima number one reactor had halted the nuclear reaction and cooling was underway. He said the reactor's pressure vessel and container appear to be sound, confining the reactor's fuel.
"It is clearly different from the case of Chernobyl, in which a reactor itself exploded and radioactive substances spread outside," he said.
The International Atomic Energy Agency has assigned the situation a level 4 status incident, meaning it currently only poses risks within the facility. Chernobyl is the only level 7 incident to have occurred to date.
The Nuclear Regulatory Commission has sent to Japan two of its officials with expertise in boiling water nuclear reactors. They joined a disaster response team with the US International Agency for International Development, the primary federal agency that provides assistance to countries struck by a disaster.
Celebrities have shown their concern over the 8.9 magnitude earthquake and tsunami.
Singing star, former American Idol finalist Adam Lambert took to social media to encourage his fans and followers to donate to the Red Cross.
Lambert wrote via Twitter: "#prayforjapan Text REDCROSS to 90999 to donate $10 to Japan's emergency relief!"
On another site, you can also order the Lady Gaga "We Pray for Japan" wristband.
Toyota Motors plans to halt operations at all of its 12 factories in Japan.
Friday's earthquake and tsunami forced the company's plants in Miyagi and Iwate Prefecture to suspend production.
Other automakers, such as Nissan, Honda and Mitsubishi will also cancel operations at either all or some of their plants from today.
The children's charity, World Vision, which normally works in developing countries, is to send staff to Japan. Spokesman Dominic Nutt told the BBC that it felt compelled to help. "The scale of this disaster is so huge that in the end we decided we had to get involved. We know that we can do some very good work with the children there."
A gallery on ABC News where you can slide over the photos to see the difference between Japan's coastal communities before and after the tsunami.
With the world watching Japan grapple with the crisis of a nuclear power plant damaged by an earthquake and tsunami, government regulators in the United States will soon be taking a close look at their own nuclear facilities to see if they're at risk from seismic forces.
There are over 100 operating nuclear power plants in America. The US is the world's largest producer of nuclear power.
About 800 Australians known to be in Japan remained unaccounted for last night although no Australian casualties had yet been reported as a result of the catastrophe.
Grave fears were held for a Melbourne man who is missing in Sendai, one of the worst-hit areas. There are thought to be at least 225 Australians in the worst affected areas.
Quake-damaged nuclear reactors pose only a low risk to New Zealand Urban Search and Rescue teams, who leave for Japan this morning.
USAR member Mitchell Brown told 3 News the team will be working no closer than 120km from the Fukushima nuclear power station.
The 48 USAR members will be part of an international USAR team based at a US Military Base north of Tokyo and will be deployed to north-east coastal areas hit hard by Friday's tsunami.
This week's earthquake in Japan could lead to insured losses of nearly US$35 billion, risk modelling company AIR Worldwide told Reuters, making it one of the most expensive catastrophes in history.
That figure is nearly as much as the entire worldwide catastrophe loss to the global insurance industry in 2010.
It could force higher prices in the insurance market after years of declines, analysts say.
A volcano in southern Japan is once again spewing ash and rock.
Shinmoedake volcano has resumed activity after a couple of quiet weeks.
The mountain is on Kyushu island, 1,500km from the epicentre of Friday's magnitude 8.9 earthquake and resulting tsunami.
Prime Minister Naoto Kan told a press conference yesterday the Japanese people "can overcome these hardships".
"The current situation of the earthquake, tsunami and the nuclear plants is in a way the most severe crisis in the past 65 years since World War II," Mr Kan said.
"Whether we Japanese can overcome this crisis depends on each of us.
"I strongly believe that we can get over this great earthquake and tsunami by joining together."
Japan's Defence Ministry says one of its naval vessels has rescued a man who spent about 45 hours at sea off Fukushima Prefecture after he was swept away by tsunami waves, Kyodo News reported.
The navy's destroyer Chokai rescued Hiromitsu Shinkawa, 60, yesterday while searching for survivors about 15km off Futaba Town. He was waving his hands and drifting on a broken roof.
Mr Shinkawa says he does not know the whereabouts of his wife.
Consular staff from the Ministry of Foreign Affairs and Trade are heading to Japan to assist New Zealanders affected by the disaster.
818 Kiwis are registered as being in Japan - none of whom are understood to be hurt.
MFAT consular staff are heading to Narita International Airport in Tokyo and Sendai in the north-east.
New Zealanders should be safe from any radiation spilling out of Japan's damaged nuclear reactors in the wake of Friday's magnitude 9 earthquake, and subsequent tsunami.
Science historian Rebecca Priestly said countries downwind of Japan should be more concerned than New Zealand.
"If you look at global circulation models, you can see that air masses tend to travel around the globe along east-west lines, rather than along north-south lines," she told The Dominion Post.
Tokyo is battling to avoid a meltdown at three quake-hit reactors at the Fukushima plant, and radiation levels were up at the Onagawa atomic plant.
More than 180,000 people have been evacuated from the affected areas.
People across a devastated swath of Japan suffered for a third day Sunday without water, electricity and proper food, as the country grappled with the enormity of a massive earthquake and tsunami that left more than 10,000 people dead in one area alone.
Japan's prime minister has called the crisis the most severe challenge the nation has faced since World War II. Friday's disasters have damaged a series of nuclear reactors, potentially sending one through a partial meltdown and adding radiation contamination to the fears of an unsettled public.