TOKYO - An earthquake with a preliminary magnitude of 5.5 struck off Aomori Prefecture in northern Japan on Sunday, the country's weather agency said.

The temblor occurred at 10:29 am local time off Aomori's Pacific coast at a depth of 50 km, measuring 4 on Japan's seismic scale of 7, said the Japan Meteorological Agency (JMA).

The quake's epicenter was located at a latitude of 40.7 degrees north and a longitude of 142.3 degrees east.

No tsunami advisory was issued.

Although a week-long alert regarding the increased risk of another strong earthquake was lifted on Monday after a 7.5-magnitude temblor struck northern and northeastern Japan on Dec. 8, JMA officials urged people to remain cautious.