A knife-carrying man was arrested Monday at the office building for members of the House of Councilors in Tokyo.The Metropolitan Police Department arrested the man, who claims to be in his 50s, on suspicion of violating the firearms and swords control law, after a staff member at the building reported to a patrolling riot police officer around 9:45 a.m. that there was a man carrying a knife. Nobody was injured.The suspect told investigators he had been instructed to bring the knife by a lawmaker he cited as 'Katayama,' the police said.