TOKYO - (AP) - Japan's nuclear regulators raised the severitylevel of the crisis at a stricken nuclear plant Tuesday to rank iton par with the 1986 Chernobyl disaster. An official with the Nuclear Safety Commission of Japan,speaking on national television, said the rating was being raisedfrom 5 to 7 - the highest level on the international scale. The official, who was not named, said the amount of radiationleaking from the Fukushima Dai-ichi nuclear plant was around 10percent of the Chernobyl accident. The level 7 signifies a "major accident" with "widerconsequences" than the previous level, according to the standardsscale. "We have upgraded the severity level to 7 as the impact ofradiation leaks has been widespread from the air, vegetables, tapwater and the ocean," said Minoru Oogoda of Japan's Nuclear andIndustrial Safety Agency. NISA officials said one of the factors behind the decision wasthat the total amount of radioactive particles released into theatmosphere since the incident had reached levels that apply to aLevel 7 incident. The action lifts the rating to the highest on an internationalscale designed by an international group of experts in 1989 and isoverseen by the International Atomic Energy Agency. In Chernobyl, in the Ukraine, a reactor exploded on April 26,1986, spewing a cloud of radiation over much of the NorthernHemisphere. A zone about 19 miles around the plantwas declared uninhabitable, although some plant workers still livethere for short periods and a few hundred other people havereturned despite government encouragement to stay away. Meanwhile, setbacks continued at Japan's tsunami-strickennuclear power complex, with workers discovering a small fire near areactor building Tuesday. The fire was extinguished quickly, theplant's operator said. Tokyo Electric Power Co., which operates the disabled FukushimaDai-ichi nuclear power plant, said the fire at a box that containsbatteries in a building near the No. 4 reactor was discovered atabout 6:38 a.m. Tuesday and was put out seven minutes later. It wasn't clear whether the fire was related to a magnitude-6.3earthquake that shook the Tokyo area Tuesday morning. The cause ofthe fire is being investigated. "The fire was extinguished immediately. It has no impact onUnit 4's cooling operations for the spent fuel rods," said TEPCOspokesman Naoki Tsunoda. The plant was damaged in a massive tsunami March 11 that knockedout cooling systems and backup diesel generators, leading toexplosions at three reactors and a fire at a fourth that wasundergoing regular maintenance and was empty of fuel.