A strong earthquake rocked the Tokyo area early Monday, causing minor damage to some buildings and delays in public transportation. There were no immediate reports of injuries.
The 6.1-magnitude quake was centered northeast of Tokyo and was focused about 36 miles underground, the Meteorological Agency said, adding that there was no danger of a tsunami.
Police said there were no immediate reports of injuries. But windows of a municipal building in Yokaichiba, a city near the quake's epicenter in Chiba prefecture (state), shattered and the roof of at least one house collapsed, city spokesman Takumi Hayashi said.
"When the quake struck, I couldn't stand up as my the whole house shook violently sideways," said Hayashi.
Public broadcaster NHK showed bottles, beer cans and cookie boxes knocked from the shelves in Chiba supermarkets and scattered on the floor.
Masahiro Yamamoto, an official at the Meteorological Agency's earthquake and tsunami division, said the quake struck in a region that has been showing active seismic activities recently and warned that there may be aftershocks.
"But strong ones that can cause damages are unlikely," Yamamoto added.
Both runways at Tokyo's Narita international airport were shut down for about 15 minutes after the temblor, but have since resumed operations, said airport spokesman Koitsu Ito. Local media reported temporary train delays as well.
Kyodo News agency said there was no damage to a nuclear facility in nearby Ibaraki prefecture (state).
A magnitude 6 earthquake can inflict widespread damage in a populated area. Last October, Japan suffered its deadliest quake in a decade when a magnitude 6.8 tremor rocked the northern Japanese region of Niigata, killing 40 people and injuring more than 2,700.
Japan, which rests atop several tectonic plates, is among the world's most earthquake-prone countries.