An altercation involving a large group of young people in Derry city centre has left one person with a head injury.
Police received a report of the clash in the early hours of Sunday, and it is believed weapons of some kind were used.
One young male believed to have been involved was found shortly afterwards with a head injury, according to police.
The incident occurred in the Artillery Street area, near St Columb’s Cathedral.
PSNI Chief Inspector Cathal Pearce has urged any witnesses to come forward.
He said: “Our enquiries are continuing to determine a motive and who was involved — we also believe weapons were used during this disturbance.
“Anyone who witnessed what happened or noticed suspicious behaviour, is asked to contact police on 101, quoting reference number 187 16/11/25.”