A man in his twenties was attacked whilst withdrawing cash from an ATM on Clanbrassil Street on Friday, October 19.
The man was waiting for cash from the bank machine at 3.30pm when he was approached by a male wearing a green and black jacket who smashed a bottle over his head and demanded cash.
Gardaí say that the injured party did not hand any money over before he made his escape by running into a nearby shop.
The injured man was taken to hospital as a precautionary measure.
Dundalk Gardaí are appealing for witnesses who might have been on the busy street last Friday afternoon to contact the local station on 042 93 88400.