A 7.3-magnitude earthquake shook Japan on Saturday, the U.S. Geological Survey reported.
The quake was off the Fukushima region of Japan, 231 miles east off the island of Honshu.
It was 6.2 miles deep, officials said, and hit at 3:10 a.m. Saturday local time and was felt 300 miles away in Tokyo.
The Japan Meteorological Agency issued a "yellow" warning Saturday morning, meaning a small tsunami could reach the coast at Fukushima, site of the 2011 nuclear power plant disaster.
There were no immediate reports of damage from the temblor, which Japanese authorities classified as a magnitude 6.8, Reuters reported. No irregularities were reported at the Fukushima nuclear plant.
A yellow warning is issued when a tsunami is not expected to exceed three feet, significantly smaller than the tsunami that hit the energy plant in March 2011. Residents in the coastal region of Fukushima Prefecture were being advised to move to higher ground.
No warning for the rest of the Pacific was posted by the U.S. Tsunami Warning Center after the quake.
NBC's Arata Yamamoto contributed to this report.