Police are searching for a man who assaulted a woman on a 5 train in the South Bronx.

The incident happened at the Third Avenue–149th Street station on Dec. 29 just before 2 p.m. Police say the man approached a 21-year-old woman on the train and punched her repeatedly on the left side of her face before fleeing on foot.

Investigators say the man was last seen wearing a blue hoodie, dark gray pants and black sneakers, and was holding a black jacket. Authorities believe he is between 21 and 25 years old.

The woman was taken to Lincoln Hospital for her injuries.

Anyone with information is asked to call the NYPD Crime Stoppers hotline at 1-800-577-TIPS (8477).