A 43-year-old man has been arrested in connection with the stabbing of a 22-year-old man in Kilkeel.
He was assaulted in Newry Street shortly before 0100 BST on Monday.
The man is being treated for a stab wound under his arm and cuts to his face. His condition is described a serious but not life-threatening.
Police are keen to speak to the occupants of a white van which drove through the area towards Newcastle and may have witnessed the incident.