A series of strong earthquakes in the Pacific Ocean shook eastern Japan and Tokyo early Thursday.

Early reports indicate the quakes caused no serious damage or injuries, and authorities say there is no risk of a tsunami.

The strongest jolt, magnitude 6.7, hit shortly before 2 a.m., local time (12:45 p.m. Wednesday EDT / 1645 Wednesday UTC). It was centered about 35 kilometers below the surface, at a spot in the ocean about 160 kilometers east of Tokyo.

Thursday's quakes rattled buildings for about an hour in the Japanese capital, where Chinese President Hu Jintao is visiting this week.

Japanese news reports quote officials as saying nuclear power facilities in the Tokyo area were not damaged by the quakes.

Japan is a center of seismic activity, since it sits atop four shifting tectonic plates in the Earth's crust.

A quake last year that was about as strong as the major shock on Thursday killed 11 people in central Japan and shut down the world's largest nuclear power plant. Japanese authorities say nuclear facilities were not affected by Thursday's earthquakes.

Some information for this report was provided by AFP, AP and Reuters.