Tokyo, Feb 27 (DPA) An earthquake with a magnitude of 6.9 struck Okinawa Prefecture, about 1,500 km southwest of Tokyo, Saturday morning, the Japan Meteorological Agency said.

A local police official told Kyodo News Agency that they had received no information of human casualties.

Police had received a report of water pipe having been ruptured in Naha city, the capital of Okinawa and Nishihara town.

The agency had issued a tsunami warning for coastal areas of the main Okinawa island soon after the 5.31 a.m. (2031 Friday GMT) quake but it was downgraded to an advisory around one hour later.

The quake originated around 10 km underground in waters near the main island.