FUKUSHIMA (Reuters/AFP) - Radiation leaked from Japans earthquake-crippled nuclear plant on Saturday after a blast blew the roof off, and authorities prepared to distribute iodine to people in the vicinity to protect them from exposure. The massive earthquake and tsunami left more than 1,100 dead and at least 10,000 unaccounted for. The government insisted radiation levels were low because although the explosion severely damaged the main building of the plant, it had not affected the reactor core container. Local media said three workers suffered radiation exposure at the plant in the wake of Fridays massive earthquake, which sent a 10-meter tsunami ripping through towns and cities across the northeast coast. Kyodo news agency said more than 1,700 people were killed or missing as a result of the 8.9-magnitude earthquake, the biggest in Japan since records began in the nineteenth century. Later it said 9,500 people in one town were unreachable, but gave no other details. The blast raised fears of a meltdown at the power facility, 240 km north of Tokyo, as officials scrambled to contain what could be the worst nuclear disaster since the Chernobyl explosion in 1986 that shocked the world. However, experts said Japan should not expect a repeat of Chernobyl. They said pictures of mist above the plant suggested only small amounts of radiation had been expelled as part of measures to ensure its stability, far from the radioactive clouds Chernobyl spewed out 25 years ago. Valeriy Hlyhalo, deputy director of the Chernobyl nuclear safety center, was quoted by Interfax news agency as saying Japanese reactors were better protected than Chernobyl. Apart from that, these reactors are designed to work at a high seismicity zone, although what has happened is beyond the impact the plants were designed to withstand, Hlyhalo said. Japans Chief Cabinet Secretary Yukio Edano told reporters the nuclear reaction facility was surrounded by a steel storage machine, which was itself surrounded by a concrete building. This concrete building collapsed. We learnt that the storage machine inside did not explode, he said. Edano initially said an evacuation radius of 10 km from the stricken 40-year-old Daiichi 1 reactor plant in Fukushima prefecture was adequate, but then an hour later the boundary was extended to 20 km. TV footage showed vapor rising from the plant. Japanese officials told the UNs atomic watchdog they were making preparations to distribute iodine to people living near nuclear power plants affected by the quake, the Vienna-based agency said. Iodine can be used to help protect the body from radioactive exposure. The wind at the disabled plant was blowing from the south, which could affect residents north of the facility, Japans national weather forecaster said, adding the direction may shift later so that it blows from the north-west toward the sea. The direction of the wind is a key factor in judging possible damage on the environment from radiation. The quake parked at least 80 fires in cities and towns along the coast, Kyodo said. Police reportedly said 200-300 bodies had been found in the city of Sendai. Some 300-400 bodies were recovered in Rikuzentakata, a coastal town of some 23,000 people, NHK quoted the military as saying. Other authorities said the tsunami had obliterated the town. The premiers spokesman said at least 1,000 people were believed to have lost their lives. Police said more than 215,000 people were huddled in emergency shelters. What used to be residential areas were mostly swept away in many coastal areas and fires are still blazing there, Kan said after surveying the damage by helicopter. Along the northeast coast, rescue workers searched through the rubble of destroyed buildings, cars and boats, looking for survivors in hardest-hit areas such as the city of Sendai, 300 km northeast of Tokyo. Dazed residents hoarded water and huddled in makeshift shelters in near-freezing temperatures. Aerial footage showed buildings and trains strewn over mudflats like childrens toys. All the shops are closed, this is one of the few still open. I came to buy and stock up on diapers, drinking water and food, Kunio Iwatsuki, 68, told Reuters in Mito city, where residents queued outside a damaged supermarket for supplies. Across the coastline, survivors clambered over nearly impassable roads. In Iwanuma, not far from Sendai, people spelled S.O.S. out on the roof of a hospital surrounded by water, one of many desperate scenes. The earthquake and tsunami, and now the radiation leak, present Japans government with its biggest challenge in a generation. The blast at the nuclear facility came as plant operator Tokyo Electric Power Co (TEPCO) was working desperately to reduce pressures in the core of the reactor. The company has had a rocky past in an industry plagued by scandal. In 2002, the president of the countrys largest power utility was forced to resign along with four other senior executives, taking responsibility for suspected falsification of nuclear plant safety records. Earlier the operator released what it said was a tiny amount of radioactive steam to reduce the pressure and the danger was minimal because tens of thousands of people had already been evacuated from the vicinity. Other media reported police roadblocks in the area to prevent people getting closer. Other nuclear power plants and oil refineries were shut down and one refinery was ablaze. Power to millions of homes and businesses was knocked out. Several airports, including Tokyo's Narita, were closed on Friday and rail services halted. All ports were shut. Nuclear power plant operator Tepco warned of severe power shortages over the weekend. Fridays tremor was so huge that thousands fled their homes from coastlines around the Pacific Rim, as far away as North and South America, fearful of a tsunami. Most appeared to have been spared anything more serious than some high waves, unlike Japans northeast coastline which was hammered by the huge tsunami that turned houses and ships into floating debris as it surged into cities and villages, sweeping aside everything in its path. I thought I was going to die, said Wataru Fujimura, a 38-year-old sales representative in Koriyama, Fukushima, north of Tokyo and close to the area worst hit by the quake. Our furniture and shelves had all fallen over and there were cracks in the apartment building, so we spent the whole night in the car ... Now were back home trying to clean. In one of the worst-hit residential areas, people buried under rubble could be heard calling out for rescue, Kyodo news agency reported earlier. Japans nuclear safety agency rated an accident at an earthquake-hit nuclear plant at four on the international scale from 0 to 7, an official said Sunday. On the International Nuclear Event Scale, a level four incident means a nuclear reactor accident with local consequences. Japans Prime Minister Naoto Kan said the chaos unleashed by Fridays 8.9-magnitude quake was an unprecedented national disaster. Russian Prime Minister Vladimir Putin on Saturday ordered a review of emergency response plans in the countrys far east after a blast at a Japanese nuclear plant, RIA Novosti news agency said. The US has transported coolant to a Japanese nuclear power plant affected by the massive earthquake, as it quickly moved naval and air assets along with humanitarian relief material for the tsunami-hit areas of the country. Meanwhile, tsunami waves from Japans huge quake have killed at least one person and sparked mass evacuations on the American continent, but failed to inflict major damage. Surges of eight feet high crashed ashore on the coasts of California and Oregon Friday, up to 12 hours after the 8.9-magnitude quake triggered tsunami alerts in dozens of countries across the Pacific. In Californias Del Norte County, a 25-year-old man was confirmed dead after being swept into the Pacific Ocean near the mouth of the Klamath River. The man and two friends were taking photographs of the incoming tsunami waves. One person was killed and houses damaged when a tsunami reached Indonesias Papua province following a devastating earthquake in Japan, state media reported Saturday.