New York Police Commissioner Jessica Tisch said the 49-year-old woman involved in the stabbing in Times Square died after police officers opened fire.
The woman took two kitchen knives from a shopping bag and first stabbed a 68-year-old man emerging from a subway station, followed by a 32-year-old woman. Both victims were taken to hospital.
The 32-year-old woman died in hospital. The 68-year-old man remains under treatment.
Police officers opened fire
Footage recorded by eyewitnesses showed the woman surrounded by at least 10 officers, refusing to drop her knives and threatening the officers.
The woman did not stop despite the use of a stun gun and moved toward the officers with the knives in her hands. Two officers then opened fire and struck the attacker.
The woman was handcuffed at the scene and taken to hospital after receiving first aid, but later died.
Investigation launched
Authorities said there was no evidence of a connection to terrorism. An investigation into the incident has been launched.