An earthquake with a magnitude of 6.8 on Tuesday struck off Yamagata Prefecture in northern Japan and a tsunami warning was issued, according to the Japan Meteorological Agency (JMA).
Tsunami warnings are in place along the coastal areas of Yamagata, Niigata and Ishikawa prefectures. The meteorological agency said there is no fear of major tsunami damage.
The temblor occurred at 10:22 p.m. local time (1322 GMT), with its epicenter at a latitude of 38.6 degrees north and a longitude of 139.5 degrees east, and at a depth of 10 km.
The quake logged upper 6 on the Japanese seismic intensity scale of 7 in the area of Kaetsu in Niigata Prefecture and lower 6 in the area of Shonai in Yamagata Prefecture.
The Secretariat of the Nuclear Regulation Authority said there are no abnormalities at the Kashiwazaki-Kariwa nuclear complex run by Tokyo Electric Power Company Holdings Inc.
East Japan Railway Co. said it partly suspended operations of its Shinkansen bullet train services connecting Tokyo with Aomori and Niigata Prefectures.
Tohoku Electric Power Company said the earthquake caused a major blackout in parts of northern Japan, with more than 9,000 households in Yamagata Prefecture and Niigata Prefecture out of power.
Japanese Chief Cabinet Secretary Yoshihide Suga, who entered the prime minister's office after 10:40 p.m. local time (1340 GMT), told reporters at an urgent press conference that authorities are still checking for injuries after the quake, adding no abnormalities have so far been detected at nuclear power plants after the quake.
Suga urged people in the affected areas to remain on alert. According to Suga, Prime Minister Shinzo Abe returned to his office following the quake, instructing government officials to do all they can for rescue and relief operations.
