TOKYO, April 2 (Xinhua) -- An earthquake with a preliminary magnitude of 6.1 struck off Japan's northern prefecture of Iwate early Tuesday, according to the country's weather agency.

       The temblor occurred at 04:24 a.m. local time at a depth of 80 km, measuring lower 5 on Japan's seismic intensity scale, which peaks at 7, said the Japan Meteorological Agency (JMA).

       The epicenter was located off Iwate prefecture's northern coast at a latitude of 40.1 degrees north and a longitude of 141.7 degrees east.

       No tsunami warnings have been issued.