A new explosion at a stricken nuclear power plant hit Japan Monday as it raced to avert a reactor meltdown after a quake-tsunami disaster that is feared to have killed more than 10,000 people.
Searchers found 2,000 bodies just in the northeastern region of Miyagi, while millions were left without water, electricity, fuel or enough food. Hundreds of thousands more were homeless after the tsunami drowned whole towns.
Panic selling saw stocks close more than six percent lower on the Tokyo bourse on fears for the world's third-biggest economy, as power shortages prompted rolling blackouts and factory shutdowns in quake-hit areas.
Kaori Ohashi, a 39-year-old mother-of-two working in a facility for the elderly with severe dementia near Sendai, spent two nights trapped in the building after its first floor was submerged by Friday's tsunami.
"Snow started to fall and it became dark. We lost power. I thought 'This is a nightmare'," Ohashi told AFP after she was saved by rescuers.
"I was so glad to see my son and daughter. I didn't have words to tell them. I was so glad," she said.
The police chief in Miyagi prefecture, which includes Sendai and took the full force of the massive tsunami following the biggest quake ever to hit Japan, said the death toll was certain to exceed 10,000 in his region alone.
At least 1.4 million people in Japan were temporarily without running water and more than 500,000 were taking shelter in evacuation centres, said the UN's Office for the Coordination of Humanitarian Affairs.
But it was the fear of a nuclear disaster looming on top of the quake and tsunami that gripped the embattled nation as it struggled with a crisis described by Prime Minister Naoto Kan as the worst since World War II.
Explosions have rocked two overheating reactors at the ageing Fukushima plant, located 250 kilometres (160 miles) northeast of Tokyo, after the cooling systems were knocked out by Friday's 8.9-magnitude quake.
A first explosion blew apart the building surrounding the plant's number-one reactor on Saturday but the seal around the reactor itself remained intact, officials said.
On Monday, shortly after Kan said the plant was still in an "alarming" state, a blast at its number-three reactor shook the facility, injuring 11 people and sending plumes of smoke billowing into the sky.
Plant operator TEPCO said a fuel rod meltdown in the number-two reactor could not be ruled out after water levels dropped sharply, Jiji Press reported. The operator later reported the rods were fully exposed and the UN's nuclear watchdog, the IAEA, said Tokyo had asked for expert assistance.
But Japan's top government spokesman Yukio Edano said a major explosion was unlikely at the reactor. Engineers were pumping seawater in to stabilise it and radiation around the plant was at tolerable levels, he said.
The World Health Organization said that there was minimal public health from the nuclear reactors.
However, authorities have declared an exclusion zone within a 20-kilometre radius of the plant and evacuated 210,000 people.
At one shelter, a young woman holding her baby told public broadcaster NHK: "I didn't want this baby to be exposed to radiation. I wanted to avoid that no matter what."
A US aircraft carrier deployed off Japan for relief efforts shifted its position after detecting low-level radiation from the malfunctioning Fukushima plant.
The ship was operating at sea about 160 kilometres northeast of the power plant at the time and a statement from the Seventh Fleet said the radiation level was so low that it presented no health risk.
Several Asian governments said they would screen food imported from Japan for radiation.
But citing advice from Russian specialists, Prime Minister Vladimir Putin said there was no "global threat" from the explosions in the Fukushima plant.
"The experts also believe there should be no nuclear explosion which could destroy the reactor," he said.
Aid workers and search teams from across the world joined 100,000 Japanese soldiers in a massive relief push as the rattled country suffered a wave of major aftershocks and a false alarm over a new tsunami.
The foreign ministry expressed its "heartfelt appreciation" for offers of help pouring in from around the world, and said rescue teams from 11 countries including China were now on the ground.
With ports, airports, highways and manufacturing plants shut down, the government has predicted "considerable impact on a wide range of our country's economic activities".
Leading risk analysis firm AIR Worldwide said the quake alone would exact an economic toll estimated at between $14.5 billion and $34.6 billion (10 billion to 25 billion euros), without taking into account the effects of the tsunami.
Rolling blackouts began across the nation in a bid to save power, with the heavily nuclear-dependent nation rocked by the crisis at Fukushima as well as an oil refinery fire.
The UN said power and gas supplies were critical, with the Japanese winter bringing sub-zero temperatures overnight and snow and rain forecast for coming days.
Russia said it was ready to divert 6,000 MW of electricity from its Far East to help Japan deal with the power shortfall.
Miki Otomo said her sister managed to escape the tsunami's black tide of wrecked houses and cars near Sendai. Others were not so fortunate.
"My older sister was in a bus when the wave came behind them. The bus driver told everybody to get out of the bus and run," Otomo told AFP. "My sister was able to get away but some people just couldn't run fast enough."
Otomo is now staying at an evacuation centre in a local school with about 1,000 other exhausted survivors who cheated death.
"We need food and clothes. Everyone had to run away before grabbing things to wear," one woman at a shelter in the small port city of Minamisanriku, where authorities say 10,000 people are unaccounted for, told NHK.
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