A man with a knife has stabbed at least 10 passengers on a commuter train in Tokyo and was arrested by police after fleeing, fire department officials and news reports say.
NHK public television said two passengers were seriously injured.
It said the suspect left his knife behind as he fled and was later arrested in Tokyo.
The Japanese capital is currently hosting the Olympics, which end on Sunday.
The Tokyo Fire Department said nine of the 10 passengers were taken to nearby hospitals, while the tenth was able to walk away.
All of the injured were conscious, fire department officials said.
NHK showed a number of police cars and people in uniform on the street where it said the suspect was arrested.
The stabbing occurred near Seijogakuen station, according to railway operator Odakyu Electric Railway Co.
The train line is mostly above ground but runs underground in the area of the attack.
Police refused to comment and no other details were immediately available.