Fears of a nuclear catastrophe in Japan are rising, as radiation leaks are at dangerous levels around a crippled nuclear power plant.
In a televised statement Tuesday, Japanese Prime Minister Naoto Kan warned that the radiation level around the Fukushima nuclear plant is "very high" and that there is risk of more radiation escaping.
Anyone living within 30 kilometers of the nuclear plant has been urged to remain indoors.
The International Atomic Energy Agency said an explosion at the Number 2 reactor may have affected the integrity of a containment structure around the reactor, increasing the risk of more radiation leaking out. Explosions also were reported Tuesday at two other reactors.
Workers have been using seawater as an emergency measure to try to cool fuel rods at the Number 2 reactor, after the cooling system was knocked out last week in an earthquake and tsunami that devastated northeastern Japan.
The fuel rods in the reactor were exposed to the air Monday, after burning through coolant faster than it could be replaced. When that happens, the rods become extremely hot and begin melting and releasing extremely high amounts of radiation.
Also Tuesday, the IAEA said a fire broke out at a storage pool for spent fuel rods at the plant's Number 4 unit, and that radioactivity was released directly into the atmosphere at dose rates equivalent to 4,000 chest X-rays every hour.
The fire has since been put out, but Japanese officials say water in the storage pool has reached a boiling point. Officials at the plant say they are considering using helicopters to add water to the pool.
All non-essential staff were evacuated from the plant before the fire was extinguished shortly before noon local time. Only a skeleton staff was retained to keep pumping seawater into three damaged reactors to try to keep the fuel rods from melting down.
Increased radiation has been detected as far away Tokyo, about 240 kilometers to the south, but officials said levels there are not a threat to public health.
Japanese citizens have been carefully watching weather forecasts for indications of which way the wind is blowing near the Fukushima plant. Forecasts called for winds from the north and northwest Wednesday, which would blow any radiation out to sea.
South Korea's Yonhap news agency says the government in Seoul has urged South Korean nationals to heed Japanese warnings and to stay away from the area around the troubled nuclear power plant. A foreign ministry official says about 2,700 Koreans are staying in Fukushima, but it is unclear how many are within 30 kilometers of the plant.
The U.S. Embassy in Japan has issued a similar advisory, urging U.S. citizens to observe all instructions given by Japanese authorities.
China is also working to evacuate its citizens from northeastern Japan. A Chinese foreign ministry spokeswoman says radiation levels in China are being closely monitored.
Nuclear power discussed
The situation in Japan has prompted several European countries to review their nuclear power programs, with Germany shutting down seven aging reactors for a safety review.
U.S. Energy Secretary Steven Chu told lawmakers Tuesday that "the American people should have full confidence" that nuclear power in the United States is generated safely and responsibly. The U.S. will send a team of 34 to Japan to help evaluate and monitor conditions at the troubled nuclear plant, Chu said. by voa