Two killed, more than 100 were injured in the northeastern Japan's earthquake measuring 7.4 on the Richter scale Thursday night, Kyodo News reported.
Japan's weather agency considered the quake as the aftershock of the devastating March 11 quake, Xinhua reported.
The agency issued a tsunami warning immediately after the 11:32 p.m. quake, whose seismic center was off Miyagi Prefecture at a depth of some 40 kilometers, but it was lifted shortly before 1 a. m. Friday.
The aftershock caused no further damage to the already crippled Fukushima Daiichi nuclear plant, operator Tokyo Electric Power Co. (TEPCO) said. Cooling-down operations resumed after the fresh quake.
Following the quake, blackouts were seen all over Aomori, Iwate and Akita prefectures as well as several parts of Miyagi and Yamagata prefectures.
In Miyagi Prefecture, expressways were closed due to the quake, while the bullet train services on the Tohoku shinkansen line were partially suspended.
Nuclear power stations in Ibaraki Prefecture were operating normally after the quake, while at the Onagawa nuclear plant in Miyagi Prefecture, which has been suspended, two external power supply units among three have failed, according to the nuclear regulator.
Tohoku Electric said operations of five units at three thermal plants in Aomori and Akita prefectures were suspended.
The temblor is one of the strongest aftershocks of the March 11 great earthquake.