TOKYO -- A strong earthquake jolted northern Japan early on Thursday, injuring several people, burying three cars under a landslide and cutting off electric power to at least 10,000 homes, media reports and officials said.

     The Japan Meteorological Agency said there was no threat of a tsunami from the quake, which had a preliminary magnitude of 6.8 and could be felt as far away as Tokyo.

     The focus of the quake was 120 km (75 miles) below the surface of the earth in Iwate prefecture, a mountainous, sparsely populated region, the agency said.

     "It was shaking so much that I almost couldn't step out of the kitchen and I panicked quite a bit. A lot of dishes broke," a man in Hachinohe city in Aomori prefecture, about 550 km northeast of Tokyo, told national broadcaster NHK.

     Japanese media said military planes were flying over the area to try to assess the extent of damage and that local authorities had requested troops be sent to the area to help. Defence Ministry officials could not immediately be reached for comment.

     "I don't have concrete information, but we've heard that there are several injured," Shinya Izumi, minister in charge of disaster management, told a news conference after the government set up an emergency task force at the prime minister's office.

     Private broadcaster TV Asahi quoted a spokesman