Tokyo - A moderate earthquake measuring 5.5 on the Richter scale hit southern Japan Sunday, the meteorological agency said, but there were no immediate reports of casualties.

There was no risk of tsunami waves, the agency said.

The tremor hit at 01:57 am (1657 GMT Saturday) and was located in seas around the Amami Islands, 250 kilometers (155 miles) south of Kagoshima prefecture and 1,300 kilometers southwest of Tokyo, the agency said.

Japan experiences 20 percent of the world's major earthquakes.