Two men are being treated in hospital in the North after trouble broke out in Derry in the early hours of this morning.
It is understood that two different groups of people were involved in the row on Irish Street in the Waterside area.
Police were called to the scene at around 3.30am and restored order.
One man is being treated for severe head injuries and a possible broken jaw, while the other suffered less serious injuries.
The PSNI is appealing for information.