Detectives who are investigating a report of an assault in the Cleary Crescent area of Newry in the early hours of Wednesday have arrested two males, aged 24 and 15, on suspicion of attempted murder.
Both males were last night in police custody.
It is understood that the arrests are in connection with an incident in which a man aged 26 was injured in a hammer attack.
The injured man also fell from a first-floor balcony during the attack, and was taken to Belfast's Royal Victoria Hospital for treatment.
A 17-year-old male appeared at Newry Magistrates' Court on Thursday in relation to the incident.
A 29-year-old man who was arrested was later released on police bail pending further enquiries.
Police enquiries are continuing and the PSNI have appealed for anyone who has any information about the incident to contact detectives on 101.