A 29 year-old Catholic man is fighting for his life after sustaining serious head injuries in an attack at a barbecue in Derry.
The PSNI in Derry have said that a sectarian motive was behind the attack which took place in the Chapel Road area of the Waterside in the early hours of this morning.
Two others who were with him were also attacked and suffered wounds that are not believed to be life threatening.
Chief Inspector Ken Finney of the Police Service of Northern Ireland's Foyle District Command Unit appealed for members of the public who knew the identities of the attackers to help police track them down.
"I utterly condemn this despicable act of violence which was carried out by unknown thugs whose sole intent was to cause serious injury," he said. "As a result a young man lies seriously ill in hospital with multiple injuries."
He added: "I am appealing to members of the public to help us identify those reprehensible act. "We are treating this as a sectarian attack. Witnesses are telling investigating officers the attackers came from the direction of Irish Street and Bann Drive."
The most seriously injured of the three victims sustained head injuries and was being treated in Altnagelvin Hospital. He is believed to come from the Prehen area of the city.
One of his friends sustained a fractured jaw and the other man was badly bruised. There were disturbances in the aftermath of the assault including an attempted hijacking in the Gobnascale area of the city.
After the intervention of local community representatives, calm was restored by 9am.
The latest assault was condemned by nationalist politicians. SDLP leader Mark Durkan, the MP for the area, said sectarianism had to be faced down.
"If prejudice and sectarianism drove these attacks, the entire community leadership must resolve to face down and root out any vestige of or excuse for sectarian hatred," the Foyle MP said.
Sinn Féin councillor Lynn Fleming said sectarianism had to be condemned from whatever quarter.
"I would appeal to people not to become involved in attacks on others as Saturday nights events clearly demonstrate how they can result in tragedy for everyone involved," the former Derry mayor said.
"No reasoning can justify this type of behaviour but if the claims that it was motivated by sectarianism are accurate it is reprehensible. Sectarianism from whatever source is to be condemned and everyone of influence must do all in their power to eradicate it."