TOKYO (AP) -- A strong earthquake with a preliminary magnitude of 6.0 struck off the coast of the southern Japanese island of Okinawa on Tuesday, Japan's Meteorological Agency said.

The agency said there was no danger of a tsunami, or seismic waves, from the quake, which occurred at 4:42 p.m. about 30 miles below the ocean's surface.

Police on Okinawa and nearby islands said there were no immediate reports of injuries or damage.

"Our building shook quite violently, but we managed to stand on our own feet, and nothing fell on the floor," said Yasumori Uezu, police spokesman in Naha City near the quake's center.

Another police official on nearby Amami Oshima island, Yukio Mukuraguchi, said the shaking lasted about 10 seconds.

"So far, we have received no injury or damage reports," he said.

Japan sits atop four tectonic plates and is one of the world's most earthquake-prone countries.

Last month a 7.2-magnitude earthquake struck sparsely populated rural areas in northern Japan, killing at least 12 people, leaving 10 others missing and injuring more than 300 people.

Okinawa is about 1,000 miles southwest of Tokyo.