A 24-year-old man stabbed several passengers on board a train in Tokyo before igniting a fire on Sunday, according to local authorities and the police.
What do we know so far?
At least 17 people were injured in the attack, with at least three people in serious condition, the Tokyo Fire Department said.
The man was reportedly dressed as the "Joker" character from the "Batman" comic book and film series. Japanese outlet NHK said the assailant was dressed in a green shirt, a blue suit and a purple coat.
The stabbing rampage occurred as partygoers travelled towards the lively neighborhood of Shinjuku to take part in Halloween celebrations.
Japanese media reported that the attacker spread a liquid around the train, lighting the carriage ablaze. The type of liquid used to start the fire is still unclear.
Has Japan witnessed any similar attacks before?
Handguns are outlawed in Japan, and the country has one of the lowest crime rates in the world. Yet, Japan has witnessed several stabbing-related incidents in recent years.
A 36-year-old man previously stabbed at least 10 people on a train in Tokyo in August a day before the Olympics closing ceremony. The suspect said the crime was motivated by women rejecting him online.
At least 19 people were also stabbed in the city of Kawasaki in May 2019. The attack targeted children who were waiting for the school bus, with the assailant having committed suicide afterward.