Police launched a murder investigation after a 21-year-old man was stabbed in Cardiff city centre.

Asim Khan, from Grangetown, died in hospital from his injuries after an incident in the early hours of Sunday morning.

A 27-year-old local man was arrested on suspicion of murder and is in custody at Cardiff Bay police station.

A spokeswoman for South Wales Police said: "Officers were called at around 4.50am today to St Mary Street following reports of an assault."

A number of officers and the police helicopter were called to the scene and a cordon was in place for a large part of the day.

Emergency services performed CPR on Mr Khan at the scene before he was taken by ambulance to the University Hospital of Wales in Cardiff where he died.

Detective Superintendent Richard Jones, from South Wales Police Major Crime Investigation Team, said: "CCTV shows a disturbance which starts in the street near McDonald's and moves towards the Oxfam store where Mr Khan sadly collapsed having sustained a wound as a result of being stabbed."

Witnesses described a suspect making-off initially in the direction of Wood Street, and then towards Penarth Road at the rear of Cardiff Central Railway station.

Anyone with information about the incident is asked to call police on 101 or anonymously via Crimestoppers on 0800 555 111 with reference 1900265784.