A strong earthquake with a preliminary magnitude of 6.9 has hit southwestern Japan, the country's Meteorological Agency said Monday, while warning the public to stay away from coastal areas because of a tsunami threat.

Tsunami advisories were issued for Miyazaki Prefecture, where the quake was centered, in the southwestern island of Kyushu, as well as nearby Kochi Prefecture, shortly after the quake struck at 9:19 p.m. local time, according to the agency.