Six off-duty police officers have been arrested following an altercation outside a pub in Co Londonderry.
Eight people in total were detained after the incident in the seaside town of Portstewart.
Three people were taken to hospital and treated for minor injuries after the fracas in the early hours of Wednesday.
Police said two of those involved in the incident were foreign nationals and a hate crime motive was being examined.
All those arrested have been released on bail pending further enquiries. It is understood the duty status of the officers is under review by police commanders.
PSNI Chief Superintendent Garry Eaton said: "This investigation is still at the early stages and we are following a number of lines of enquiry including reviewing CCTV footage and identifying and speaking to witnesses.
"I would encourage anyone who was in the area of Church Pass in Portstewart during the early hours of Wednesday and witnessed the altercation to contact detectives in Coleraine.
"Discipline branch is also conducting an internal investigation and therefore it would not be appropriate for me to comment further, however what I can say is that the Police Service of Northern Ireland expects its officers and staff to behave professionally, ethically and with the utmost integrity at all times.
"Any deviation from those standards is unacceptable and we are committed to ensuring that where officers and staff fail to maintain the high standards expected of them they are dealt with appropriately."