A 66-year-old woman was punched in the face aboard a northbound 6 train, and her attacker remains on the run, police say.

The incident unfolded as the train doors opened at the 138th Street subway station just after 2 p.m. Monday.

Authorities say the woman was sitting on the train when the man punched her in the face and ran away.

EMS treated the woman for her injuries, which police say were minor.

Anyone with information is urged to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477).