The suspect was caught in the act, as the incident was captured on security video.
Police say he grabbed a woman's iPhone from her shirt pocket and pushed her to the ground.
It happpened on Friday morning as she entered the West 157th Street subway station along the southbound '1' line.
The 37-year old victim suffered injuries to her knee and wrist.
The suspect fled the station.
He's described as a black or Hispanic male, approximately 20 years old, 5'6"-5'8", medium build. He was last seen wearing a green shirt, grey jeans and white sneakers.
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