A strong earthquake jolted Tokyo early Monday, rattling windows and nerves though there were no initial reports of major damage.
The national broadcaster NHK, citing local authorities, said 17 people were reported injured, some of them from falls as the quake struck.
The Japan Meteorological Agency said the quake at 5.18 am (local time) had a magnitude of 6.0 and was centered 160 kilometres under the seabed near Izu Oshima island south of Tokyo.
The quake was felt across a wide area of Japan, with the strongest shaking registered in central Tokyo, the agency reported. Tokyo Fire Department reported that four people were injured, but details were not immediately available.
NHK reported some delays in train services on Monday and said speed restrictions were imposed briefly on expressways in the affected area as a precaution.