At a press conference on Tuesday, the agency reported that the aftershocks were observed less frequently, but the aftershocks of magnitude 7 or more is still possible.
Officials have warned that aftershocks could destroy buildings, already damaged by the earthquake and tsunami, or trigger another powerful tsunami.
Earlier it was reported that in the east coast of Honshu Island on Tuesday, seismologists have recorded about two dozen earthquakes of varying magnitude - from 4.5 to 6.6. New data on the destruction and the victims are not.