A woman was arrested after allegedly slashing and stabbing other passengers with a blade on a train on Tokyo's Yamanote loop line on Wednesday night, police said.

The woman, believed to be in her 20s, attacked passengers as the train was running between JR Okachimachi and Akihabara stations, the police said, adding that she was apparently unknown to those assaulted.

Four men, who are in their 30s to 60s, sustained injuries to their sides, backs and arms in the attack, the police said.

Investigative sources said Thursday that the suspect has told police that she wanted to "kill people." Police are investigating the suspect's identity.

According to the sources, the suspect is believed to have attacked the victims with a knife that was roughly 15 centimeters long. Another knife was found in her bag.

Responding to the attack, passengers pressed emergency buttons installed in the train and on the platform of Akihabara Station once the train arrived, and a station staffer called the police at around 10:55 p.m.

Passengers on the train subdued the woman and handed her over to the police, who arrested her on suspicion of attempted murder and seized the blade, the police said.

The incident led JR East to temporarily suspend part of the Yamanote Line service in the capital.