A knife and arson attack on an underground train line in Tokyo has left 17 injured, local media say.
Police arrested a 24-year-old man, who was wearing a costume similar to the Joker character from the Batman comics.
The attack happened as many people headed for Halloween parties. Witnesses say the suspect sprayed a clear liquid around the carriage and set it alight.
Video footage showed passengers running through carriages away from flames and clambering out of train windows.
The attack happened at around 20:00 local time (11:00 GMT) near Kokuryo station, in the city's western suburbs. Eyewitnesses said the suspect was wearing a bright purple and green suit.
"I thought it was a Halloween stunt," one witness told the Yomiuri newspaper about the attack. "Then, I saw a man walking this way, slowly waving a long knife."
The AP news agency, citing the Tokyo Fire Department, said three of the injured had serious wounds. Local media reports an elderly man was unconscious after being stabbed in the attack.
Video from the scene shows passengers running from the attacker, stumbling through a connecting door between carriages and climbing through the train's windows after it made an emergency stop.
Shunsuke Kimura, who filmed one of the videos, told the national NHK broadcaster that the scene was "horrifying". "Train doors were closed and we had no idea what was happening, and we jumped from the windows," he said.
The suspect, who was arrested at the scene, told authorities he "wanted to kill people so he could be sentenced to death", local media reported.
Violent crime is rare in Japan but there have been a number of high-profile knife attacks in recent years.
Ten people were injured by a knife-wielding man on another Tokyo commuter train in August. In 2019, a man attacked a group of schoolchildren waiting for a bus in Kawasaki, killing two and injuring at least 18 others.