The Tokyo Electric Power company has announced that the Fukushima Daiichi and Fukushima Daini nuclear power plants have not been damaged by 7.4-magnitude earthquake that hit Japan Thursday night.

The earthquake occurred at 11:32 pm local time, its epicenter was located 40 km off the east coast of Japan below the sea bed, Japanese state TV NHK reported.

A tsunami warning has been issued as a result of the new strong earthquake; a one-meter high tsunami is expected to hit the coast of northeastern Japan.

Japan's meteorological agency has urged evacuation of the coastal areas of the Miyagi prefecture.

The Tokyo Electric Power Company (TEPCO) has announced that the new earthquake has not affected the situation in the Fukushima Daiichi nuclear power plant, which was badly damaged by the March 11 earthquake ushering into one of the world's worst nuclear crises ever.

All TEPCO workers from Fukushima Daiichi and Fukushima Daini have taken shelter, and are reported to be safe.

A spokesperson of TEPCO announced on NHK TV that the company is continuing its water injection of reactors 1, 2, and 3 at the Fukushima Daiichi NPP as well as the injection of nitrogen into reactor 1, which are part of its measures to contain the crisis situation caused by the March 11 earthquake.

The Onagawa NPP, however, has been affected as only one of the three power transmission lines of the plant remains functioning. According to the authorities, it is sufficient to maintain the operations on the spot. The three reactors at Onagawa were turned off after the March 11 earthquake.

The Japan nuclear safety agency has announced that no radiation leaks have been detected.