A magnitude 6.9 earthquake hit off Japan's southern coast early Saturday, shaking Okinawa and nearby islands, where a tsunami warning was issued, Japan's Meteorological Agency said.
The quake occurred off the coast of the island of Okinawa at a depth of 6.2 miles (10 kilometers) at 5:31 a.m. Saturday (2031 GMT Friday), the agency said.
It predicted a tsunami up to 6 feet (2 meters) near the Okinawan coast. There were no immediate reports of major damage or casualties.
Ryota Ueno, a town official in the Nishihara district of Okinawa, said, "I was fast asleep when the quake hit, and I jumped out of bed. It felt like the shaking lasted forever."
There was no major damage in his house, and he then rushed to the town office to meet up with his colleagues and stand by in case of reports of damage from residents, Ueno told a telephone interview with public broadcaster NHK.
So far, only one resident reported a ruptured water pipe, but no other damage reported, he said.
Okinawa is about 1,000 miles (1,600 kilometers) southwest of Tokyo.
Japan is one of the world's most earthquake-prone countries. In 1995, a magnitude-7.2 quake in the western port city of Kobe killed 6,400 people.