A tornado ripped through eastern Japan on Sunday, killing a teenager, destroying dozens of houses and cutting power to about 20,000 households.
"A 14-year-old male died" as a result of the tornado, said a spokesman at the disaster headquarters of Tsukuba city in Ibaraki prefecture, about 60km northeast of Tokyo.
The exact cause of the death was not clear immediately, but the boy was among 12 people whom rescue workers rushed to hospitals after the twister, the spokesman said.
He added that 15 other people in the city also sought medical care for tornado-related injuries. "The figure is only a temporary tally. We believe the number (of injuries) could rise," he said.
The Tsukuba fire and emergency bureau said 30 to 50 houses were destroyed by the tornado, which struck about 12.45pm (1345 AEST).
A number of minor injuries were also reported in neighbouring Tochigi prefecture, and a swathe of eastern Japan was battered by strong winds, hail, lightning and heavy rain.
Television footage from Tsukuba showed houses swept from their foundations, overturned cars in muddy debris and fallen concrete power poles.
Aerial images showed possibly hundreds of houses and apartments with shattered glass windows, many of them with their roofs blown away.
"You could see the roaring column of wind rushing with sparks from live power lines inside it," a local man told national broadcaster NHK.
"Winds blew into my house. It took only a moment," a woman told NHK while cleaning up her home.
Japan's weather agency issued warnings for a wide region in the east of the country, urging people to seek shelter in case of sudden winds and thunder.
The severe winds caused a power outage for nearly 20,000 households in the region, a spokeswoman for Tokyo Electric Power said.