A major earthquake of magnitude 7.6 has hit Japan's north-eastern region.
The quake occurred at 23:15 (14:15 GMT) at a depth of 50km (31 miles), about 80km off the coast of the Aomori region, the Japan Meteorological Agency reported.
It prompted tsunami warnings which have now been downgraded to advisories, while waves of 40cm (16in) were observed in some locations.
Local media indicates that injuries have been reported, and trains were suspended as a precaution.
Japan is one of the world's most earthquake-prone countries, recording tremors every five minutes.
More than 90,000 residents were ordered to evacuate, as reported by Reuters news agency.
According to NHK, an employee at a hotel in Hachinohe reported several injuries.
The government has established a response office at the Prime Minister's crisis management center and convened an emergency team, as stated by chief cabinet secretary Minoru Kihara.
We are making every effort to assess the damage and implement emergency disaster response measures, including rescue and relief operations, he emphasized.
No irregularities were reported at the Higashidori and Onagawa nuclear power plants following the earthquake, according to Tohoku Electric Power.
Authorities also confirmed that no issues were detected at the disabled Fukushima nuclear power station site, reassuring the International Atomic Energy Agency.
The earthquake comes as a stark reminder of Japan's vulnerability, as the nation still remembers the catastrophic events triggered by a 9.0 magnitude earthquake on March 11, 2011, which resulted in a devastating tsunami and the Fukushima disaster.
