The death toll rises to 17 in a fire that occurred on a train west of Tokyo, caused by a passenger armed with a knife.
According to the authorities, one of the stabbed people, around 60 years of age, is in serious condition.
The police arrested a 24-year-old man - who, according to the first testimonies, would have poured oil inside the train, before setting fire to the seats of the carriages.
The operator of the Keio line warned the conductor that he stopped the convoy at Kokuryo station, before suspending services in both directions.
Images taken by mobile phones show people fleeing from a moving wagon inside which an explosion can be seen.
Other photos posted on social media depict passengers trying to get out of the train carriage windows once they arrive at the station.