Tokyo, April 12 (IANS) A strong 6.3 magnitude earthquake jolted northeastern parts of Japan Tuesday afternoon, the Japan Meteorological Agency said.

 
 The temblor occurred at 2.07 p.m. (0816 GMT), Xinhua reported. There were no immediate reports of casualties or damage to properties.
 
 Tremors were felt in Fukushima and Ibaraki prefectures.
 
 No abnormalities have been found so far in external power sources at the Fukushima nuclear power plant, the plant's operator said. But workers at the plant were told to evacuate.
 
 The crisis level of the accident at the Fukushima plant has been raised from the earlier five to seven, the worst on an international scale, Japan's Nuclear and Industrial Safety Agency said Tuesday.
 
 The plant has been releasing 10,000 terabecquerels of radioactivity per hour, which is an official benchmark for a level-7 event, according to RIA Novosti.