Parts of Japan have been devasted by the most powerful earthquake to hit the country in at least 100 years. The offshore quake measuring 8.9 magnitude has unleashed walls of water that swept across rice fields, engulfing towns, dragging houses on to highways and tossing cars and boats above. Local media reported at least 32 deaths, with more casualties feared. The quake that struck at 2:46 p.m. local time prompted issue of a tsunami warning for at least 20 countries. The quake's epicenter was 373 kilometers away from Tokyo. But residents there continued to feel aftershocks hours after the quake. More than 30 aftershocks followed, with the strongest measuring at 7.1. Japanese Prime Minister Naoto Kan has appealed for calm and said there are no reported leaks of radioactive materials from power plants. Four nuclear power plants closest to the quake were safely shut down, the UN nuclear watchdog agency said. At Tokyo Station, one of Japan's busiest subway stations, shaken commuters grabbed one another to stay steady as the ground shook. Dazed residents poured into the streets after offices and schools were closed. Children cried. Residents said though earthquakes are common in Japan, Friday's stunned most people. The quake toppled cars off bridges and into waters underneath. Waves of debris flowed like lava across farmland, pushing boats, houses and trailers. About 4 million homes had no power in Tokyo and surrounding areas. Shenza Chen of the U.S. Geological Survey says at such a shallow depth, earth quake creates a lot of energy. Firefighters battled a blaze at an oil refinery in Chiba prefecture near Tokyo. As the city grappled with the devastation, a massive tsunami swept across the Pacific Ocean. In Philippines alone, the tsunami is expected to hit in the early morning and the government has evacuated 20 provinces along the coast. Authorities in at least 20 countries and numerous Pacific islands issued tsunami warnings. A tsunami warning has now been issued for virtually the entire Pacific coast including Australia, South America and parts of the United States. The International Red Cross in Geneva said a huge wave driven by the earthquake could be higher than some of the Pacific islands in their path. But several hours after the biggest earthquake struck, there was no word of damage outside Japan. To the north, the Russian authorities said small waves had reached the Kurile islands. Taiwan reported minor tsunami. Indonesia's eastern areas including Papua, Maluku and Sulawesi are on guard. Union Home Ministry said in New Delhi today that there is no threat to the Indian coast in the wake of the huge tsunami that devastated Japan. In a statement the Ministry said the Hyderabad-based Indian National Centre for Ocean Information Services has ruled out any threat to India. Humanitarian agencies were working with rescue crews to reach the people affected. New Delhi says there are no reports of any casualties from the Indian community due to earth quake and tsunami in Japan. There are 25,000 Indians living in Kanto and Kansai regions of Japan. A spokesman of the External Affairs Ministry said in New Delhi that Indian Embassy in Tokyo and Couselate in Osaka are in touch with the Indian community members and verifying situation on the ground. It said a control room has been established in the Embassy of Tokyo and the phone number is 00813-32622391 to 397. He said that the Ministry is monitoring the situation closely and will take all necessary steps required to meet any exigency. The Prime Minister Dr. Manmohan Singh and the External Affairs Minister Mr. S. M. Krishna have spoken to their counterparts offering India's help in the hour of crisis and conveyed heartfelt condolences to the bereaved families. Expressing sympathies and condolences with the government and people of Japan, New Delhi says it is saddened by the loss of life and extensive damage to property and infrastructure in Japan due to this natural calamity.