Japan on Friday revised down Thursday's earthquake magnitude from 7.4 on the Richter scale to 7. 1, Japan Meteorological Agency said.

The quake, hit the sea near Miyagi Prefecture in northeastern Japan at 23:32 p.m. local time (1432 GMT) Thursday. The focus of the quake was located some 40 km under the sea off the northeastern prefecture of Miyagi, said the agency.

Three people were killed and over 100 were injured in the fresh quake, which caused no further damage to the crippled Fukushima Daiichi nuclear plant.

The weather agency considered the quake as the aftershock of the devastating March 11 quake, which killed 12,731 people dead and left 14,706 others unaccounted for as of 10:00 a.m. local time (0100 GMT) Friday.