( AP ) - A 6.7-magnitude earthquake jolted northwestern Japan on Monday morning, killing at least three people and injuring more than 400 others. The quake flattened dozens of wooden houses and triggered a fire at a nuclear power plant.
The area was plagued by a series of aftershocks, the strongest of which was magnitude 5.6. There were no immediate reports of additional damage or injuries from the aftershocks.
Three elderly women in Kashiwazaki were killed by the initial quake, hospital officials said. National broadcaster NHK reported more than 400 people were hurt.
"I was so scared - the violent shaking went on for 20 seconds," Ritei Wakatsuki, an employee of convenience store Lawson, told The Associated Press by telephone from Kashiwazaki. "I almost fainted by the fear of shaking."
The U.S. Geological Survey said the quake registered 6.7 magnitude. Koichi Uhira of Japan's Meteorological Agency warned that the aftershocks could continue for a week.
Flames and billows of black smoke poured from the Kashiwazaki nuclear plant. The fire, at an electrical transformer, was put out shortly after noon and there was no release of radioactivity or damage to the reactors, said Motoyasu Tamaki, a Tokyo Electric Power Co. The reactor and two others in the region had shut down automatically.
Some 2,000 people in Kashiwazaki were evacuated from their homes, city official Takashi Otsuka said.
NHK reported nearly 300 buildings in the city had been destroyed. The force of the quake buckled seaside roads and bridges, and one-yard wide fissures could been seen in the ground along the coastline.
A ceiling collapsed in a gym in Kashiwazaki where about 200 people had gathered for a badminton tournament, and one person suffered minor facial injuries, Kyodo reported. The quake also knocked a train car off the rails while it was stopped at a station. No one was injured.
The Meteorological Agency issued tsunami warnings along the coast of Niigata state, but the warnings were later lifted. Waves up to 20 inches were believed to have hit the coast, but no damage was reported.
Several bullet train services linking Tokyo and northern and northwestern Japan have been suspended. Officials said water and gas services for Kashiwazaki's 35,000 households were suspended after reports of gas leaks, reports said. About 18,000 households were without power as of Monday afternoon.
The quake, which hit the region at 10:13 a.m., was centered off the coast of Niigata, 160 miles northwest of the capital, Tokyo. The tremor made buildings in Tokyo sway and was also felt in northern and central Japan.
Prime Minister Shinzo Abe, campaigning in southern Japan for parliamentary elections later this month, was to return to Tokyo to deal with the quake, and the government had set up a task force, reports said.
Niigata Airport, which had suspended flights shortly after the quake, resumed services after finding no damage, Kyodo said.
Japan sits atop four tectonic plates and is one of the world's most earthquake-prone countries. The last major quake to hit the capital, Tokyo, killed some 142,000 people in 1923, and experts say the capital has a 90 percent chance of suffering a major quake in the next 50 years.
In October 2004, a magnitude-6.8 earthquake hit Niigata, killing 40 people and damaging more than 6,000 homes. It was the deadliest to hit Japan since 1995, when a magnitude-7.2 quake killed 6,433 people in the western city of Kobe.