Three men are recovering in hospital after a suspected sledgehammer attack in Derry.
The PSNI were called to an incident in the Waterside area of the town in the early hours of this morning.
Police had received a report from a member of the public that a number of men were seen walking along Bonds Street armed with a sledgehammer and hammers shortly before 1:40am.
Paramedics responded and found three men, two aged in their 30s and one in his 40s, with injuries from an apparent violent attack.
Detective Sergeant Ray Phelan said: "We believe the three men were the victims of an unprovoked and cowardly attack by four assailants armed with weapons.
Police are exploring a potential link to loyalist paramilitaries as part of our enquires.
"We are working to establish how the men sustained their injuries, who was responsible, what the circumstances were leading up to the incident and we are making a number of appeals.
The PSNI are appealing for members of the public who may have witnessed an altercation to come forward.