TOKYO: Thousands of Japanese and US troops launched an intensive air and sea operation Friday to recover bodies still left from the huge earthquake and tsunami three weeks ago. The grim search came as the government revealed radiation from a nuclear power plant crippled by the twin disaster had been found in groundwater, with contamination already reported in the air, ocean and food. Japan is still struggling to cope with its worst post-war crisis three weeks after the seafloor quake struck on March 11, leaving about 28,000 people dead or missing. In the search for bodies, Japanese and US armed forces deployed 120 aircraft and 65 ships for a three-day operation along the northeast coast, where houses, ships, cars and trains still lay scattered across the muddy wastelands. Prime Minister Naoto Kan told a briefing that the radiation leaking from the Fukushima nuclear plant presents no public health threat as long as people follow the government's advice. “Japan decides on the area (of evacuation around the plant) based on experts' advice and proposals,” he said. “In Japan, we ask people to follow the rules because if they do, there will be no damage to their health.” Kan, who had donned emergency worker uniform since the disaster, switched to business attire Friday, showing that he now was looking to “the next stage” of restoration, government spokesman Yukio Edano said. Kan was Saturday to fly to the devastated port of Rikuzentakata, and “J-village”, the base for hundreds of emergency crew who have battled at great risk to prevent a nuclear meltdown at the crippled Fukushima power plant. At the Fukushima plant, which has been leaking radiation, workers started spraying resin on the rubble of blast-hit reactor buildings as part of their tense stop-and-go effort aimed at shutting the plant down. The environmental impact was worsening, with high levels of iodine-131 found in groundwater 15 meters (50 feet) below the plant's reactor number one, and at more than 4,000 times the maximum safe level nearby in the Pacific Ocean. Vegetable, dairy and other food shipments from four prefectures in the area have been stopped because of radiation, which the health ministry said has now also been found in beef from 70 kilometers (40 miles) away. However, Tokyo Electric Power Co (TEPCO), the plant's operator, is reviewing previously disclosed radiation data after it found problems with its computer analysis of the radioactive material tellurium, the nuclear safety agency said. The government has issued assurances that no water or food contamination had yet reached levels that would have an immediate impact on public health.