Authorities sought the help of the US military in tackling the "extremely tough" situation at the plant, close to which highly concentrated radioactivity was detected in iodine and cesium in seawater, sparking fears about food safety.
The nuclear plant's operator, Tokyo Electric Power Company (TEPCO), said the seawater pollution in the region had expanded, but the country's nuclear safety agency said there were no immediate health threats.
The amount of radioactive iodine reached 80.3-fold of the standard level at the point 8 km south of the plant and 16.4-fold at the point 16 km south, Kyodo news agency reported.
The Fukushima prefectural government denied the possibility that seafood from the area was distributed to markets saying fishing had not been conducted near the nuclear plant, where emergency workers battled to avert a widespread disaster by trying to reconnect power lines and cool overheating reactors.
The critical restoration work at the plant was stalled yesterday after smoke rose from No.2 and No.3 reactors, fuelling fears of fresh radiation leaks from the area rocked by the March 11 quake of magnitude 9 and devastating tsunami that left over 22,000 people dead or unaccounted for in Japan's northeast.
Although white smoke, possibly steam, was still found to be billowing from the No.2 and No.3 reactors, TEPCO said it was not obstructing electricity restoration work.
Firefighters and the Self-Defense Forces (SDF) personnel were also ready to restart their mission to spray tonnes of coolant water onto spent nuclear fuel pools at the No.3 and No.4 reactors, according to TEPCO.
The US Geological Survey, meanwhile, said that two 6.6-magnitude quakes and one measuring 6.4 on the Richter Scale were reported within two and a half hours off Japan's northeastern Honshu coast, starting from 1248 IST. However, there were no reports of casualties or damage.
Japan's National Police Agency said the number of those killed or were unaccounted for following the devastating March 11 earthquake and tsunami topped 22,000.
It said the death toll reached 9,080 in 12 prefectures, while 13,561 people remained missing in six prefectures.
The cooling systems -- designed to protect the plant's six reactors from a potentially disastrous meltdown -- were knocked out by the earthquake and tsunami that struck Japan's northeast Pacific coast on March 11.
On Monday, TEPCO finished laying cables to transmit electricity to the No. 4 reactor, as a step toward resuscitating the power systems at the No. 3 and No. 4 reactors, according to the utility and the nuclear agency.
The plant operator was also trying to restore a ventilation system to filter radioactive substances from the air and some measuring equipment at the control room of the No. 2 reactor, but this mission remained uncompleted due to the temporary evacuation.
It may take more time before the vital cooling system is restored at the No. 2 reactor, the containment vessel of which suffered damage to its pressure-suppression chamber, as some replacement parts are needed for the electrical system, the agency added.
Amid fears of contamination, the government ordered Fukushima and three other prefectures hit by the disaster to suspend shipments of spinach and another leaf vegetable following the detection of radioactive substances in the produce.
Radioactive substances were also detected in tap water samples collected in nine prefectures, Kyodo said.
The government's nuclear disaster countermeasure headquarters also asked Fukushima to refrain from shipping raw milk.
Yukio Edano, the Chief Cabinet Secretary, said the readings for radioactive substances found in the produce were at levels exceeding provisional limits set under the Food Sanitation Law but "aren't readings that would affect humans."
"Eating food with (radioactive levels) exceeding provisional limits isn't going to affect your health," the the top government spokesman said.
Authorities have also started tests to determine the possible impact on fish following radioactive contamination in the food supply.
Even as authorities struggled to cope with the massive humanitarian crisis, the World Bank said the disaster could cost Japan up to USD 235 billion.
On the nuclear crisis, Defence Minister Toshimi Kitazawa said the smoke rising from the No.2 reactor at the Fukushima plant were vapours caused by water-discharging operations. He said the blackish smoke was detected yesterday at No.3 reactor as some rubble had caught fire after a rise in temperature.
Japanese defence authorities have also sought support of the US military to jointly tackle the ongoing nuclear crisis and coordination is underway, Kitazawa said.
SDF helicopters will begin measuring "drastically changing" temperatures at the plant daily except for rainy days to "relieve people's concerns," instead of the earlier planned twice a week, he said.
An external power source was connected to the No.4 reactor this morning, making it the fifth of the plant's six reactors to have regained the power supply needed for the restoration of a ventilation system to filter radioactive substances from the air and some measuring tools at the control room, Kyodo said.
Following the powerful quake and tsunami, the cooling functions failed at the No.1, No.2 and No.3 reactors and their cores are believed to have partially melted.
Industry Minister Banri Kaieda said separately that the situation remained "extremely" tough. "It is difficult to say that things are showing progress...," he was quoted as saying.
Prime Minister Naoto Kan had yesterday said that slow but "steady progress" is being made in tackling the brewing crisis at the quake-hit power plant.
TEPCO, meanwhile, began studying the crisis' impact on the sea after detecting highly concentrated radioactive substances near the Fukushima plant's water discharging outlets.
The Vienna-based IAEA also said the Japanese authorities have reported that they will measure radioactivity in the marine environment around the Fukushima plant. The monitoring will be done by the Japan Agency for Marine-Earth Science and Technology, results of which will be provided on Thursday, it said.
The Japanese government may need to create three different supplementary budgets for fiscal 2011 to finance reconstruction work after the devastating earthquake, National Policy Minister Koichiro Gemba said.
"Damage is widespread. (Drawing extra budgets) twice will likely not be sufficient," Gemba was quoted as saying by Kyodo after a Cabinet meeting.
Finance Minister Yoshihiko Noda also said that it is necessary for the ruling and opposition parties to swiftly discuss the budget.
"I would like to benefit from the expertise" of the opposition camp, Noda was quoted as telling the House of Councillors Budget Committee.
In the severely damaged prefectures of Iwate, Miyagi and Fukushima, at least 125 children and students from kindergarten to college levels were killed and 1,600 remained missing following the March 11 disaster, authorities said.
As fuel shortage made it difficult to cremate the bodies, two municipalities in Miyagi Prefecture -- Higashimatsushima and Watari -- started burying them after gaining consent from the families.
Nine other municipalities in Miyagi as well as Kamaishi and Otsuchi in Iwate prefecture will follow suit, Kyodo said.
In Higashimatsushima, 24 bodies were buried today, with many of them wrapped in sheets as there were not enough coffins. Four bodies were buried at a temple in Watari.
The Higashimatsushima city government said it has marked a large portion of land for burial of up to 1,000 bodies. Two other municipalities planned to cremate the bodies probably within two years, officials were quoted as saying.
A total of 270,000 evacuees, including those who fled areas around the crisis-hit nuclear plant, were now staying at about 1,900 shelters in 16 prefectures.
The prefectural government of Osaka started accepting applications from the evacuees for its public housing which will be offered for free, while Nagasaki prefecture said it has decided to accommodate some 1,700 evacuees at private hotels and hot spring inns for up to two months without any charge.
