The Japan Meteorological Agency says a moderate earthquake has jolted southern Japan, but there are no reports of damage or injuries.
The agency says the quake, with a preliminary magnitude of 5.2, rocked Okinawa Island just after midnight local time Thursday. The agency says the quake was centered 50 kilometers underground.
Authorities say there is no danger of a tsunami.
Earthquakes are common in Japan, one of the world's most seismically active areas.
Some information for this report was provided by AFP and AP.