TOKYO -- An earthquake has struck close to Tokyo, shaking much of the metropolitan region. There were no immediate reports of injuries or damage, and no tsunami risk.

The Japan Meteorological Agency said the 7:41 a.m. Friday morning quake had a preliminary magnitude of 4.6. The epicenter was in Kawasaki city, just south of the border with Tokyo.

Japanese broadcaster NHK reported that the quake briefly interrupted bullet train service between Tokyo and Odawara, a nearby city to the south.