A man armed with a knife has killed seven people and injured 11 others in central Tokyo, Japanese media say.
The incident occurred in the Akihabara district, a busy shopping area known as Electric Town that is popular with young people and tourists.
A suspect, said to be 25-year-old Tomohiro Kato, has been arrested near the scene.
The stabbing came on the anniversary of a 2001 knife attack which killed eight children at a primary school.
A police spokesman, Jiro Akaogi, confirmed Mr Kato's identity and arrest.
"The suspect told police that he came to Akihabara to kill people," Mr Akaogi told reporters.
"He said he was tired of life. He said he was sick of everything," he added.
Earlier reports suggested he could have been a gangster.
The dead include six men, ranging in age from 19 to 74, and a 21-year-old woman, Kyodo News said.
Reports say the suspect drove a rented truck into a crowd in the early afternoon and then began stabbing people at random.
James Slaymaker, a British man working in Japan, got to the area shortly after the stabbings. He described the scene to BBC News:
"As I walked down the street, I noticed there were a lot of police cars. I noticed there was a guy literally just lying there with tape on his eyes and blood pouring out of the side of him. I was appalled.
I could see carnage - bodies everywhere. Some were conscious, some were not, lying by the side of the road and on the road. There were people everywhere, a lot of onlookers."
Another eyewitness told Kyodo News: ''The man jumped on top of a man he had hit with his vehicle and stabbed him with a knife many times. Walking toward Akihabara station, he slashed nearby people at random
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