A man armed with a knife has killed seven people and injured 10 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. Police spokesman Jiro Akaogi told reporters: "The suspect said he came to Akihabar