A magnitude 6.1 earthquake struck off eastern Japan early Thursday, the Japan Meteorological Agency said, rocking buildings in the capital Tokyo and surrounding prefectures. No tsunami warning was issued.

The 4:47 a.m. quake, which originated at a depth of about 36 kilometers, registered as lower 5 on nation's shindo seismic intensity scale of 7 in the city of Asahi, Chiba Prefecture. The agency warned that quakes of similar intensity may follow over the next week in areas that experienced strong swaying.

An intensity of lower 5 means people are likely to become frightened and feel the need to hold onto something stable, according to the agency.

"After a shock that felt like something pushing up from below, swaying lasted for 30 seconds to 1 minute," said a male clerk at a convenience store in Asahi. "But nothing fell off shelves and no glasses broke."

A woman in her 80s broke her left leg after she woke during the quake and fell down in her home in Ichihara, Chiba, where tremors measuring an intensity of 4 on the shindo scale were recorded, according to authorities.

There were no reports of landslides or major damage to buildings.

The quake was also felt across central and northeastern parts of the nation. East Japan Railway Co. said it briefly suspended services on some sections of its lines in Chiba Prefecture following the quake.

No abnormalities were reported at the Tokai No. 2 plant run by Japan Atomic Power Co. in neighboring Ibaraki Prefecture, according to the prefectural government.

Chiba and Ibaraki prefectures have experienced increased seismic activity recently.

More information: