Saturday, a 7.0-magnitude undersea earthquake occurred off northeastern Japan shortly after 23:00 local time (1400 GMT), and was also felt by Tokyo residents for a short period. There was no warning of a tsunami. 

The Japanese Meteorological Agency reported that the earthquake occurred at a depth of 60 km in the Pacific Ocean off the Fukushima region, which was previously devastated by an earthquake and tsunami on March 11, 2011, causing a nuclear disaster and leaving 18,000 dead and missing.

Kyodo News reported that at least four people were injured, without providing further details.

950,000 homes were cut off from electricity in the northeast, according to the government.

TEPCO, the operator of the Fukushima Daiichi Nuclear Power Plant, which was previously severely damaged in March 2011, announced that it is monitoring the impact of the earthquake on its facilities.

Japanese Prime Minister Yoshihide Suga went to his office while the government formed a special cell to follow up on the development of the situation in the affected areas, according to the public channel NHK.

The Japan Meteorological Agency said that Saturday's earthquake was followed by aftershocks, one of which reached 4.7 magnitude.

"The damage, losses and structural damage are being estimated," Chief Cabinet Secretary Katsunobu Kato told reporters after midnight, adding that the express train was suspended in part due to power cuts.

He explained, "Surveys are taking place at the Fukushima Daiichi nuclear plant, and we have received reports that the Onagawa nuclear reactor and the Fukushima Daiichi nuclear plant do not show any defects."

Japan is located on the Pacific "Ring of Fire," a region experiencing intense seismic activity that extends from Southeast Asia and encompasses the Pacific Basin.

In September 2018, a 6.6-magnitude earthquake jolted Hokkaido, causing landslides, collapsing homes and killing more than 40 people.