At a downtown grocery store, a line of anxious mothers cleaned the shelves of bottled water seven minutes after the doors opened. At an organic farm on the city’s outskirts, a group tested spinach with a hand-held radiation detector. And at the prime minister’s headquarters, the chief cabinet secretary announced that Japan is considering importing drinking water. 
 
 As emergency crews battled Thursday to contain nuclear fallout from the earthquake-hit Fukushima Daiichi power plant in northeast Japan, a nervous uncertainty spread as far away as Tokyo, 150 miles to the southwest, as radiation was reported in parts of the food chain and millions tried to understand the implications. 
 
 In Vienna, the International Atomic Energy Agency reported Thursday that Japanese scientists have found “measurable concentrations” of radioactive iodine-131 and cesium-137 in samples of seawater collected off the Fukushima prefecture coast. 
 
 “The iodine concentrations were at or above Japanese regulatory limits, and the cesium levels were well below those limits,” the IAEA said on its Web site. The samples were gathered Tuesday and Wednesday at several points 18.6 miles from shore, the U.N. nuclear watchdog agency said. 
 
 A day after Tokyo officials warned of elevated iodine levels in the city’s tap water and the national government restricted shipment of 11 leafy vegetables in several prefectures, residents scrambled to stock up on the essentials, which are now in short supply. 
 
 Tokyo officials distributed 240,000 bottles of water to households with infants, who are more vulnerable to radioactive iodine-131. The U.S. Embassy handed out to American citizens potassium iodide pills, which can block radioactive iodine from building up in the thyroid gland. 
 
 “If the situation isn’t better in one week, I actually might have to move in with my parents,” said Yuki Ochiai, 32, mother of an 8-month-old girl who was among two dozen customers in line at the Tokyu grocery store 20 minutes before it opened. “My husband is already encouraging me to leave.” 
 
 As residents fretted, the number of deaths from the March 11 earthquake and tsunami officially topped 10,000, the National Police Agency said Friday. More than 17,000 people remain missing. 
 
 Two weeks after the quake, Japan Prime Minister Naoto Kan is scheduled to address the nation at 7:30 p.m. Friday, his spokesman said. 
 
 Meanwhile, the struggle to prevent more radiation from escaping the nuclear plant continued. Engineers hooked up lighting to a control room at the unit 1 reactor Thursday — an incremental, but hopeful, step toward cooling overheated spent fuel rods. At the unit 3 reactor, workers prepared to test a cooling pump that would allow them to pour in fresh rainwater instead of less effective seawater. 
 
 But there were setbacks. Three workers suffered radiation burns after stepping in contaminated water while attempting to lay electrical wiring at one of the buildings. Two of the workers, exposed to 170 to 180 millisieverts of radiation, were hospitalized, said Chief Cabinet Secretary Yukio Edano, who did not disclose the status of the third employee. The Associated Press quoted Fumio Matsuda, a spokesman for the Nuclear and Industrial Safety Agency, as saying that radiation levels of 170 to 180 millisieverts were well below the maximum 250 millisieverts allowed for workers. 
 
 Officials said Friday they are investigating possible damage to the reactor vessel at unit 3 that could be allowing dangerous radiation to leak into the atmosphere. 
 
 Government authorities said they are analyzing the reactor’s vessel, pipes and valves for potential damage that could be causing a leak. That reactor is considered particularly dangerous because it is the only one that burns mox fuel, a combination of plutonium and uranium that is hotter than conventional uranium reactors. 
 
 “Looking at the data, we believe the No. 3 vessel still has the capacity to contain radioactive material,” Hidehiko Nishiyama, deputy director-general of the Japan Nuclear and Industrial Safety Agency, said at a news conference. “But we have to investigate … the possibility the No. 3 reactor has sustained damage.” 
 
 The setback is the latest in a fitful effort to contain nuclear fallout at the Daiichi power plant. Crews have attached power cables to try to restore electricity, but only two of the six facility’s six reactors have successfully been put into cold shutdown. Twice this week, workers were evacuated after smoke was seen rising from the buildings, though officials later said the smoke was caused by steam that is not harmful. 
 
 The nervous uncertainty over the food chain Thursday sent people sifting through information about the complicated and rapidly changing problem. In Chiba and Saitama, two prefectures neighboring Tokyo, officials discovered iodine levels exceeding the legal limit for infants. Yet Tokyo’s water, which had tested high a day earlier, showed a decrease Thursday. 
 
 For some, the brief water warning was a tipping point, a sign that the environment had become a threat. At the Tokyu grocery, an employee opened the store doors at 10 a.m. and a half-dozen pregnant women and young mothers rushed to the far aisle. 
 
 Within seven minutes, all 80 two-liter bottles were gone. Ochiai, cradling her daughter, held two of them. Her parents, who live in Hokkaido, a northern island, were sending 12 more bottles of water by airmail, she said. 
 
 “I actually feel sorry standing here with my two bottles of water,” Ochiai said. “All these other mothers are here now, and they are too late.” 
 
 As parents worried about supply, farmers brooded over the demand for their food, tainted by the government’s advisory that residents not eat 11 leafy vegetables grown in prefectures near the Daiichi facility, citing elevated levels of radioactive materials in them. 
 
 The advisory has left farmers nationwide wondering about the effect on their livelihood as consumers weigh the risks. 
 
 At a spinach farm in Chiba, about 11 / 2 hours outside Tokyo, the proprietor, Masayuki Kumate, 45, looked on as Sumito Hatta, a food researcher, used a dosimeter to take a radioactivity reading of a lone row of green plants sprouting from the dark brown soil. 
 
 Kumate shook his head. Although Chiba officials had not banned any produce, Kumate said he has “been worried since Day One” of the disaster. 
 
 “It’s so clear what was going to happen,” he said of the nuclear fallout. “For Fukushima farmers, it is impossible [to recover]. The soil is contaminated. They will have to get rid of that before they start again. It takes a very long time. It will be a very big problem.” 
 
 Hatta and a friend, Shinya Takeda, started a blog and a Facebook page dedicated to informing the Japanese people and the world about the plight facing Japan’s farmers and asking for donations. 
 
 Japan’s Ministry of Agriculture, Forestry and Fisheries sent a letter to banks this week encouraging them to provide loans to farmers seeking to rebuild. And the government has pledged that the Tokyo Electric Power Co., which operates the nuclear plant, will provide stipends to farmers whose crops have been contaminated. 
 
 “The farmlands that were soaked with saltwater will not be revived as farmland,” the Facebook page reads. “This reality is another destruction for the farmers. . . . Now people in Japan are buying up all food at supermarkets and oil at gas stations due to the anxiety. Our food sovereignty is in great danger.” 
 
 Special correspondents Akiko Yamamoto and Kyoko Tanaka contributed to this report. ||||| Shirakawa, Japan (CNN) -- Japanese authorities are operating on the presumption that possible meltdowns are under way at two nuclear reactors, a government official said Sunday, adding that there have been no indications yet of hazardous emissions of radioactive material into the atmosphere. 
 
 The attempts to avert a possible nuclear crisis, centered around the Fukushima Daiichi facility in northeast Japan, came as rescuers frantically scrambled to find survivors following the country's strongest-ever earthquake and a devastating tsunami that, minutes later, brought crushing walls of water that wiped out nearly everything in their paths. 
 
 Chief Cabinet Secretary Yukio Edano told reporters there is a "possibility" of a meltdown at the plant's No. 1 reactor, adding, "It is inside the reactor. We can't see." He then added that authorities are also "assuming the possibility of a meltdown" at the facility's No. 3 reactor. 
 
 A meltdown is a catastrophic failure of the reactor core, with a potential for widespread radiation release. 
 
 The efforts to control the temperature of atomic material, by pumping in sea water and boron, are taking place at the same facility where four were hurt late Saturday in an explosion. Edano said only a "minor level" of radiation has been released into the environment -- saying it all came from a controlled release of radioactive steam, insisting there have been no leaks. 
 
 "We do not believe it is harmful to human health," he said. 
 
 About 180,000 people are being evacuated from within 10 to 20 kilometers (6 to 12 miles) of the Daiichi plant -- which is in addition to the thousands that have already been taken away who live closer by. More than 30,000 more people were being evacuated from their homes within 10 kilometers of the Fukushima Daiini nuclear facility located in the same prefecture. 
 
 The news of the possible meltdowns came as rescue efforts resumed Sunday morning in areas devastated by the 8.9-magnitude quake and subsequent tsunami, which unleashed a wall of seawater that decimated entire neighborhoods. 
 
 Rescuers dug through mud and rubble to find the buried, both alive and dead. Japan's Prime Minister Naoto Kan said more than 3,000 people have been rescued, according to the nation's Kyodo News Agency, some of them plucked from collapsed homes, muddy water and burning debris. 
 
 While the official death toll from Japan's National Police Agency was at 763, with 639 missing and 1,419 people injured. The actual toll is thought to be much higher, with Japanese public broadcaster NHK reporting more than 900 dead and Kyodo News Agency saying the death toll could top 1,800. 
 
 The number is expected to rise as rescuers reach more hard-hit areas. In one coastal town alone -- Minamisanriku, in Myagi Prefecture -- some 9,500 people, half the town's population, were unaccounted for, Kyodo reported. 
 
 With most stores and gas stations closed, a main task for many in the hardest-hit areas Sunday morning was getting by -- and, in some cases, getting out. Scores lined up at the few gas stations, drug stores and grocery stores that had opened, with the shelves largely empty amid the rush to get food and the difficulty in restocking it. 
 
 They also braved an seemingly endless barrage of aftershocks. The U.S. Geological Survey reported more than 140 such quakes -- magnitude 4.5 and higher, including a 6.2-magnitude quake just before 10:30 a.m. Sunday -- in, near or off of the east coast of the Japanese island. 
 
 Friday's quake was centered about 130 kilometers (80 miles) from Sendai. The city, with a population of about a million, is located in a farming region already battling youth population losses to big cities, leaving aging residents struggling to keep up with the global economy. 
 
 While there was little visible damage in that city, the devastation -- most of it caused by the tsunami, which reached several miles inland -- was readily apparent in coastal areas. 
 
 In the city of Shirakawa, south of Sendai, rescuers dug through rubble with shovels to try to reach 13 neighbors trapped when the earth opened up and swallowed their homes. 
 
 Relatives and friends stood in the cold, with temperatures near freezing overnight, quietly watching, praying and waiting. Others wept. 
 
 In other affected areas, military choppers plucked people from rooftops. In some cases, rescuers trudged in muddy water, carrying survivors on their backs. Weary, mud-spattered residents wandered through streets filled with crumpled cars and other debris. 
 
 Meanwhile, millions more around Japan were dealing with other repurcussions of Friday's quake. 
 
 The quake disrupted rail service and affected air travel. Flight cancellations left at least 23,000 people stranded in two Tokyo airports, Kyodo said. Departing and arriving flights resumed Saturday. Limited rail service also was back in operation Saturday. 
 
 Tokyo's Disneyland and Tokyo Disney Sea will close for 10 days, Kyodo News Agency reported, one of a host of closings, cancellations and other disruptions in the quake's aftermath. 
 
 About 2.5 million households -- just over 4% of the total in Japan -- were without electricity Sunday, according to Fujisaki, the nation's U.S. ambassador. This marks a steep drop from the previous number, when 6 million households had no power. 
 
 A desire to conserve power prompted decisions to turn off lights Saturday at a host of landmarks all around Japan -- some of them hundreds of miles from the main quake's epicenter, like the Tsutenkaku Tower in Osaka, Tokyo Tower and Rainbow Bridge in Tokyo, and Bay Bridge in Yokohama, the Kyodo News Agency reported. 
 
 Japan plans to dispatch 100,000 members of its Self-Defense Forces to the quake-ravaged region -- double the previous number -- Defense Minister Toshimi Kitazawa said Sunday, according to the Kyodo News Agency. 
 
 Japan's government also has made a formal request for U.S.aid, including military support, and full planning for deployment is in effect, with the U.S. military in Japan taking the lead, according to Sgt. Maj. Stephen Valley with U.S. Forces Japan. 
 
 The nuclear-powered aircraft carrier USS Ronald Reagan, along with a guided-missile cruiser and destroyer ship, arrived off Japan's coast Sunday morning to support Japanese forces in disaster relief operations, the U.S. Department of Defense said in a statement. 
 
 The U.S. Agency for International Development has sent two search and rescue teams, from Virginia and California. Those teams, of about 150 people and 12 rescue dogs trained to find survivors, were expected to arrive Sunday morning and immediately begin working alongside Japanese and international teams. 
 
 At least 48 other countries and the European Union also have offered relief to Japan, and supplies and personnel are already on the way. 
 
 The quake was the latest in a series around Japan last week. 
 
 On Wednesday, a 7.2-magnitude earthquake struck off the coast of Honshu, the country's meteorological agency said. Early Thursday, an earthquake with a preliminary magnitude of 6.3 struck off the same coast. 
 
 Friday's quake is the strongest earthquake in recorded history to hit Japan, according to U.S. Geologic Survey records that date to 1900. 
 
 The world's largest recorded quake took place in Chile on May 22, 1960, with a magnitude of 9.5, the USGS said. 
 
 CNN's Tom Watkins, Anna Coren, Kyung Lah, Paula Hancocks, Brian Walker, Kevin Voigt and Sean Morris contributed to this report. ||||| RIKUZENTAKATA, Japan -- The elderly couple fled their home on foot as the warning sirens blared. But they could not keep up with their neighbors and fell behind as the tsunami rushed in. 
 
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 Nearly a week later, 71-year-old Taeko Kanno and her husband are still missing. 
 
 "I think there is no hope," said Katsuo Maiya, Kanno's brother-in-law. "I can't find them. The only thing I can do is wait until the military collects their bodies." 
 
 As retrieving bodies increasingly becomes the focus of rescue crews in Japan's northeast, it's clear that Friday's earthquake and tsunami – believed to have killed more than 10,000 – took their heaviest toll on the elderly in this rapidly aging nation, where nearly one in four people is over 65. 
 
 Many, unable to flee, perished. Survivors lost their daily medicines. Hospitals lost power and water. Sometimes, the consequences have been fatal. 
 
 Friday's twin disasters also crippled a nuclear power plant in the northeast, adding to the region's woes. Fourteen older patients died after being moved to a temporary shelter in a school gym because their hospital was in the evacuation zone near the overheating plant. 
 
 Two of the patients died in transit Monday and 12 more at the gym, said Chuei Inamura, a Fukushima government official. It took until Thursday to get all the remaining patients into other hospitals. 
 
 "We feel very helpless and very sorry for them," Inamura said. "The condition at the gymnasium was horrible. No running water, no medicine and very, very little food. We simply did not have the means to provide good care." 
 
 At least some international rescue teams ended their efforts Thursday, acknowledging there was little prospect left of finding missing people still alive. 
 
 "We have no more tasks," said Pete Stevenson, a firefighter heading Britain's 70-strong team. "The Japanese government have told us they are now moving from search and rescue to the recovery phase." 
 
 He insisted their departure wasn't related to any fears of radiation from the troubled Fukushima nuclear plant, which lies about 90 miles (150 kilometers) south. 
 
 Japan's relatively large elderly population presents a particular challenge for rescue and relief in what is already a disaster of epic proportions. 
 
 About 23 percent of Japan's 127 million people are age 65 or over, nearly double the proportion in the United States. 
 
 Japan's rural areas have been in decline for years, and many of the small coastal towns hit hardest by the tsunami had seen an exodus of young people moving to cities for work. 
 
 Now the low-lying parts of those towns have been flattened, and as much as half the population in some may have been killed. The official death toll climbed over 5,300 Thursday and is expected to top 10,000. 
 
 Kanno, the woman who couldn't keep up with her neighbors, comes from one such town – Rikuzentakata, a port city that was home to 20,000 before the disaster. 
 
 When the tsunami surged into Rikuzentakata, her 67-year-old sister Masako Maiya rushed down from her home in the hills with her husband, Katsuo. 
 
 They only got as far as a bridge. Down below, they saw the town had become a muddy inland sea. 
 
 One of Kanno's neighbors told them she saw Kanno and her husband flee, but the couple was slow and had lagged behind. 
 
 For five days, the Maiyas went from morgue to morgue, looking for the Kannos' bodies. On Thursday, they decided to visit the site where their home stood. 
 
 "The house should be around here," Masako Maiya said, stopping in front of a pile of splintered wood and mud. 
 
 A pained moan escaped from her husband's mouth. "There's nothing," he said, taking off his glasses and wiping tears from his eyes. His wife began to sob too. Still crying, they turned and walked away. 
 
 In the town of Kamaishi, American and British rescue teams completed their final sweeps, and Japanese mechanical diggers began the task of clearing collapsed homes, offices and stores. 
 
 Crews found more than a dozen bodies, some trapped underneath homes flipped on their roofs, another at the wheel of his overturned car. In three days of searching the battered coast, they found no survivors. 
 
 "There are probably dozens of bodies we just can't reach," said Heather Heath, a 38-year old British firefighter. "The water can force people under floorboards and into gaps we can't search. It's such a powerful force." 
 
 For survivors, in a still-wintry climate, the battle is to keep the elderly healthy and alive. 
 
 A hospital in Tagajo was cleaning off muddy medicine Thursday and trying to keep its 90 patients alive without water or electricity. A large generator and two portable toilets were delivered by the Japanese military. 
 
 "We've been told we'll get medicine sometime next week," said Daisuke Toraiwa, a physical therapist at the hospital. 
 
 The tsunami killed 47 of the 113 residents at a retirement home in the city of Kesennuma. Those who could escaped to the second floor. But many got wet, and 11 more died over the next two days because of the cold, said owner Morimitsu Inawashida. 
 
 Today, the 53 survivors live in a basketball gym, some sitting in wheelchairs with thick blankets wrapped around them. A nurse from a nearby hospital checks their blood pressure. With snow falling outside, kerosene heaters help keep them warm, but Inawashida said the fuel is running out. 
 
 "They are alone and under high stress," he said. 
 
 At a school turned shelter in the same city, a group of older men and women sat in the large drafty gym, warmed only be a single kerosene heater. A few ointment tubes, bandages and boxes of aspirin and stomach and cold medicines were stacked on a nearby table. 
 
 "It's freezing, there are people who are sick and injured," Keiko Endo, a 58-year-old nurse at the shelter, said. "People are mostly putting up with whatever's wrong. We're trying to comfort and help them, but we can't do too much." 
 
 Doctors Without Borders, the international assistance group, has seen cases of hypothermia, serious dehydration and respiratory diseases in some shelters, said Eric Ouannes, general director of the group's Japan affiliate. The tsunami washed away many people's medications. 
 
 "Some don't remember what they were taking, how much, and what was the exact prescription," he said. "So that makes things a little more complicated." 
 
 Despite the hardships, many survivors take heart in the cameraderie of sharing a common fate. 
 
 "If everyone's got nothing, everyone's got the same," Isao Nagai, 62, said, standing in a cold junior high school gym in Ofunato. About 150 survivors huddled under blankets. Some dozed, others talked or read the newspaper. "There's a comfort we get from each other. It's simple. We've all got nothing. Not half or some. Nothing." 
 
 Kinuyo Kojima, whose house in Ofunato was washed away, agreed. 
 
 But, the 65-year-old woman said, "We live like animals." The stench of backed-up toilets has made some retch, and they complain of constipation from the diet of rice and little or nothing else. 
 
 "You should have seen us when we got a piece of chicken yesterday," Kojima said Thursday. "We were so excited over a tiny piece of meat. It had been so long." 
 
 Mineko Ohira, a 63-year-old nursery school teacher in Ofunato, worries about the elderly, and what will happen when they have to leave the shelters and find themselves bereft of friends, family and homes. 
 
 "The country should find a way to help support them," she said.
– A sad milestone out of Japan: Two weeks after the quake struck, its official death toll has broken the 10,000 mark—and that number is still on the rise, with more than 17,400 missing. Police estimate the toll will surpass 15,000 in the hardest-hit prefecture alone. Among survivors, hundreds of thousands remain in temporary shelters, 660,000 homes lack water, and 209,000 have no electricity. And with the damage expected to cost as much as $310 billion, it’s set to be the most expensive natural disaster in recorded history, the AP reports. Japan has extended the evacuation zone from a 12-mile radius around the troubled Fukushima plant to an 18-mile one, notes the Los Angeles Times. Water is in short supply as bottles fly off the shelves; the government is weighing importing drinking water. Even in Tokyo, 150 miles from the plant, there are reports of radiation in the food chain. The government has now restricted sales of 11 leafy vegetables, prompting farmers’ fear for their livelihood, reports the Washington Post.