A 14 year-old boy died as a result of the tornado, a city official said
A tornado ripped through eastern Japan on Sunday, killing a teenager, destroying dozens of homes and cutting power to around 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, roughly 60 kilometres (37 miles) northeast of Tokyo.
The exact cause of the death was not immediately clear, but he was among 15 people whom rescue workers rushed to hospitals immediately after the twister, the city government said.
It added that 21 other people also sought medical care for tornado-related injuries in the city, and said it had asked Self Defense Force troops to help with rescue and relief operations.
"The figure is only a temporary tally. We believe the number (for injuries) could rise," the spokesman said.
The Tsukuba fire and emergency bureau said 30 to 50 houses were destroyed by the tornado, with many more damaged.
Moka city in neighbouring Tochigi prefecture reported one injury and damage to 132 buildings after it was hit by a separate apparent tornado.
A number of minor injuries were also reported in Tochigi, while a swathe of eastern Japan was battered by strong winds, hail, lightning and heavy rain.
In total, tornadoes damaged roughly 500 houses and buildings in the Kanto region, including Ibaraki and Tochigi, said the online editions of national broadcaster NHK and the mass-circulation Yomiuri Shimbun newspaper.
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, said a spokeswoman for Tokyo Electric Power.
"The tornado and thunder happening around 12:46 pm (0346 GMT) are believed to be the cause of the outage for 19,300 clients in Tsukuba and its surrounding areas," she said.