Photo/Illutration Police officers near JR Akihabara Station at 11:30 p.m. on Jan. 3. (Yoichiro Kodera)

A woman injured at least four men in a knife attack on a Yamanote Line train in Tokyo late on Jan. 3 before being subdued by other passengers and arrested by police.

The Metropolitan Police Department received an emergency call around 11 p.m. about a woman brandishing a knife and injuring people on the train.

She was arrested at JR Akihabara Station in Tokyo’s Chiyoda Ward on suspicion of attempted murder.

The woman, in her 20s, is believed to have slashed several people. Four men were stabbed in the stomach, back or arm, but all were said to be conscious, according to the Manseibashi Police Station.

The motive for the attack remains unknown, police said.

A 24-year-old victim said he was sitting on the train when he felt a sharp pain in his right chest. A kitchen knife fell to the floor in front of him, and a woman was standing silently nearby, he said.

East Japan Railway Co. said the incident disrupted outbound services on the Yamanote Line, a normally busy line that circles central Tokyo.