The strongest earthquake felt in Tokyo since the aftershocks of the March 2011 tremblor that left thousands dead or missing, rattled nerves and caused no major damage early Monday.
The Japan Meteorological Agency said the quake at 5:18 a.m. local time had a magnitude of 6.0 and was centered 99 miles under the seabed near Izu Oshima island south of Tokyo.
The national broadcaster NHK, citing local authorities, said 17 people were reported injured, some of them from falls as the quake struck. There were no initial reports of major damage.
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.
The national broadcaster NHK said it was the strongest quake felt in the Japanese capital since the aftershocks of a magnitude-9 earthquake and tsunami in March 2011 off the northeastern coast that left more than 18,500 people dead or missing.
There were no reports of damage or other abnormalities from the Fukushima Dai-Ichi nuclear plant, which was crippled in the 2011 disasters, leading to the closures of all Japan's nuclear reactors for safety checks.
NHK reported some delays in train services Monday and said speed restrictions were imposed briefly on expressways in the affected area as a precaution.
Japan is situated at the meeting place of several of the Earth's tectonic plates and experiences a number of relatively violent quakes every year. But due to strict building codes, powerful quakes that might wreak havoc in other countries often do little damage in Japan.
Elsewhere in the Pacific, Reuters reported a magnitude 6.6 earthquake struck in the Pacific Ocean on Sunday deep in the ocean about 328 miles south of Suva, Fiji, the U.S. Geological Survey said.
The USGS initially estimated the earthquake 6.8 magnitude and revised that to 6.6. It reported a second earthquake of magnitude 6.1 about 10 minutes later, further south.
The second earthquake was 379 miles deep, USGS said. No tsunami warning was issued by the Pacific Tsunami Warning Center.