|Tsunami waves hit he coast in Fukushima prefecture after a 9.0-magnitude earthquake on March 11 [AFP]
The top US nuclear regulator has said the quake and tsunami-ignited Japanese nuclear crisis appear to be on the verge of stabilising.
Bill Borchardt, the commission's executive director for operations, said that units 1, 2 and 3 at the Fukushima Daiichi plant have some core damage but that containment for those three reactors is not currently breached.
However, a plume of smoke from two buildings on Monday temporarily stalled critical work to reconnect power lines and restore cooling systems.
Al Jazeera's Andrew Thomas, reporting from Morioka, said it remained unclear on Tuesday morning what had caused the smoke.
"TEPCO, the company that runs the plant, say they're not too concerned," he said. "They say radiation levels seem to be stable and that smoke may just have been a bit of an aberration."
Efforts to restore electricity to the plant were resumed on Tuesday morning.
In the days since the March 11 earthquake and tsunami wrecked the plant's cooling systems, reactors have overheated and some explosions have occurred.
“Our crisis is still going on. Our crisis is with the nuclear plants. We are doing everything we can to bring this to an end,'' Yuhei Sato, governor of Fukushima prefecture, where the plant is located, told about 1,400 people who were moved away from areas around the plant to a gymnasium 80km away.
Growing concerns about radiation add to the chain of disasters Japan has struggled with since the 9.0-magnitude quake devastated the country.
There is mounting evidence of radiation in vegetables, water and milk causing the government to ban sale of raw milk, spinach and canola from prefectures over a swathe of land from the plant toward Tokyo.
|Authorities say the quake-triggered tsunami left
more than 350,000 homeless [GALLO/GETTY]
The government has also started to test fish and shellfish.
The operator of the stricken plant, Tokyo Electric Power Company (TEPCO), said a small trace of radiation had been found in the Pacific sea waters nearby.
Radioactive iodine in the sea samples was 126.7 times the allowed limit, while caesium was 24.8 times over, Kyodo news agency said. That still posed no immediate danger, TEPCO said.
"It would have to be drunk for a whole year in order to accumulate to one millisievert," a TEPCO official said,
referring to the standard radiation measurement unit.
China, Japan's biggest trading partner, ordered testing of Japanese food imports for radiation contamination and the World Health Organisation (WHO) said Japan will have to do more to reassure the public about food safety.
“They're going to have to take some decisions quickly in Japan to shut down and stop food being used completely from zones which they feel might be affected,'' Gregory Hartl, a WHO spokesman, said.
WHO said Japan needs to act quickly and ban food sales from areas around the damaged Fukushima nuclear plant if the food there is found to contain excessive levels of radiation.
Death toll rising
Yukiya Amano, the UN nuclear agency chief, said on Monday international nuclear safety standards will need to be strengthened after the crisis triggered by an earthquake and tsunami.
But the director general of the International Atomic Energy Agency (IAEA) acknowledged it could be difficult to make such rules mandatory.
Safety issues are the responsibility of individual countries and the IAEA is not a "nuclear safety watchdog", he said.
Police officials say that the death toll from the massive earthquake and tsunami is likely to exceed 18,000.
Hitoshi Sugawara, a police spokesman, said on Monday that Miyagi, one of the hardest-hit prefectures, might account for 15,000 deaths alone.
"It is very distressing as we recover more bodies day by day," Sugawara said.
The National Police Agency said the overall number of bodies collected so far stood at 8,928 while 12,664 people have been listed as missing.The World Bank said in a report on Monday that Japan may need five years to rebuild from the disasters. The damage is estimated at around $250 billion, making it the world's costliest ever natural disaster.
Japan's economic growth is expected to depress in the first half of this year before reconstruction kicks in.
The quake that triggered a 10-metre tsunami obliterated towns, which are now wastelands of mud and debris, leaving more than 350,000 people homeless.
Al Jazeera and agencies