A woman has died after being set on fire by an apparent stranger on a New York City subway train. Police arrested a suspect who is alleged to have sat watching his victim burn.

The woman, who has not been identified, was sitting on the motionless train in a station at about 7.30am (12.30pm GMT) on Sunday when a man calmly used a lighter to set her clothes on fire, the New York Police Department (NYPD) said.

The man left the train as police on patrol in the station rushed to help. The officers used extinguishers to put out the fire and the woman was pronounced dead at the scene by the emergency services.

“What [the officers] saw was a person standing inside the train car fully engulfed in flames,” Jessica Tisch, the NYPD commissioner, told a press conference.