SENDAI: Japanese crews grappling with the world’s worst nuclear incident since Chernobyl contended with a new fire and feared damage to a reactor containment vessel Wednesday as the nation reeled from a quake-tsunami disaster.

With nerves on edge across the world’s third-biggest economy and beyond, people across Asia have been stripping shelves of essentials for fear of a major emission of radiation from the stricken Fukushima nuclear power plant.

However, after the Tokyo stock exchange’s biggest two-day sell-off in 24 years sparked a global market rout, the headline Nikkei share index recovered 4.37 percent on Wednesday morning as investors snapped up bargains.

The Bank of Japan pumped another 3.5 trillion yen into the financial system, adding to trillions spent this week since Friday’s 9.0 magnitude earthquake and tsunami crippled a large swathe of the economy.

Authorities are staring at a staggering death toll. The devastation in tsunami-hit areas such as the small fishing town of Minamisanriku is absolute, with the northeastern settlement missing about half of its 17,000 residents.

“Ten of my relatives are missing. I haven’t been able to get in contact with them,” 54-year-old Tomeko Sato, who lost her house in the disaster, told AFP.

“I was very surprised by the power of the tsunami, next time, I will live on the hill and hope it never happens again.”

At the crippled Fukushima atomic plant 250 kilometres northeast of Tokyo, live TV footage showed a cloud of white smoke rising high into the clear blue sky.

The containment vessel around reactor number three may have suffered damage, and the “likeliest possibility” for the white cloud was that steam was escaping from the vessel, chief government spokesman Yukio Edano said.

The number-three reactor was hit by a blast Monday that tore off the outer structure of the reactor building.

Fire crews fought a new blaze early Wednesday at reactor number four, operator Tokyo Electric Power (TEPCO) said, but it was later extinguished.

Engineers have been desperately battling a feared meltdown at the 40-year-old plant since the earthquake and tsunami knocked out cooling systems and fuel rods began overheating.

There have now been four explosions and two fires at the complex, with four out of its six reactors in trouble.

France’s Nuclear Safety Authority said the disaster now equated to a six on the seven-point international scale for nuclear accidents, ranking the crisis second only in gravity to the level-seven Chernobyl disaster in 1986.

Yukiya Amano, the Japanese chief of the UN’s atomic watchdog, said Tuesday there might be limited core damage at the second reactor but repeated that he did not think the situation could escalate to rival Chernobyl in Ukraine.

“I continue to think that the Chernobyl and Fukushima reactors are different,” the head of the International Atomic Energy Agency said.

Amano reiterated that unlike Chernobyl, the Fukushima reactors have primary containment vessels, and had also shut down automatically when the earthquake hit, so there was no chain reaction going on.

Japanese crews said they may pour water from helicopters, if necessary, to stop spent fuel rods at Fukushima from being exposed to the air.

Eight experts from the US Nuclear Regulatory Commission were heading to Japan Wednesday to help advise on the crisis.

President Barack Obama, who has dispatched a naval flotilla led by a US aircraft carrier to aid in the quake-tsunami rescue operation, said he was “deeply worried” about the potential human cost of the crisis.

Obama also vowed to “further improve” the safety of US atomic facilities, while several European nations announced reviews of their own nuclear installations and Germany temporarily shut down seven reactors.

Hoax emails and text messages warning of radiation drifting south from Japan set off a run on essentials such as bottled water and fresh milk in places as far afield as the Philippines on Tuesday.

Japan’s government has warned that panic-buying could hurt its ability to provide aid to areas devastated by Friday’s natural disaster, which has left 3,373 confirmed dead. Many thousands more are still missing.

But scared Tokyo residents filled outbound trains and rushed to shops to stock up on face masks and emergency supplies amid heightening fears of radiation headed their way.

Radiation levels around the Fukushima facility again rose strongly on Wednesday morning before falling, officials said, while in Tokyo they see-sawed on Tuesday without ever reaching harmful levels.

The government has warned people living up to 10 kilometres beyond a 20-kilometre exclusion zone around the nuclear plant to stay indoors.

More than 200,000 people have already been evacuated from the exclusion zone.