An earthquake with a preliminary magnitude of 6.1 hit northern Japan on Saturday, March 19, broadcaster NHK said. The epicenter was not far from Japan's stricken nuclear power plant.

There was no tsunami threat and no immediate reports of injuries or damage, NHK added. Japan has been hit by hundreds of aftershocks since a massive earthquake and tsunami smashed the northeast coast on March 11, triggering a nuclear power crisis, Reuters reports.

More than a week since the magnitude-9 earthquake struck off Japan’s northeast coast, hundreds of thousands of people are homeless and the government is struggling to restore supplies of power and fuel. Panic buying by Tokyo residents worried about a nuclear leak from a power plant north of the city began to ease, as convenience stores and supermarkets restocked.