A man has sustained "potentially life-threatening" injuries after he was attacked in a house.
The assault occurred in the early hours of Monday morning in the Cornshell Fields area of Derry.
Police in Northern Ireland say four men who are thought to have been involved in the incident reportedly fled the scene in a Volkswagen Golf.
Detectives are appealing for witnesses following the serious assault, Belfast Live reports.
A PSNI spokesman said: "Shortly after 2am it was reported that a 28-year-old male was attacked in a house in the area.
"He was taken to hospital for treatment for potentially life threatening injuries where his condition is described as critical.
"Three other men and two women, who were also in the house at the time, were not injured.
"Four males, who are believed to have been involved in the incident, are reported to have made off in a grey coloured Volkswagen Golf.
"Detective Sergeant Richard Donnell is appealing for anyone who witnessed the incident or anyone who may have seen a grey coloured Volkswagen Golf in the area at the time to contact Detectives in Strand Road on 101 quoting reference 107 02/12/19.
"Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime."
