Toyosi Shittabey, 15, was taken to hospital after the attack in Tyrrelstown, north-west Dublin, shortly after 7pm on Friday but died a short time later.

Two brothers, aged in their 20s and 30s, were arrested shortly after the killing which happened at Boulevard Mount Eustace.

The teenager was of Nigerian descent but had been living in Ireland for some years.

A garda spokesman said: "I don't think anyone went out there to kill anyone. But things got out of hand and then someone was killed.

"This is certainly an incident which we are addressing from the point of view of is it racist based."

Detectives believe an altercation took place outside a house at Mount Garrett Rise.

A short time later, around 150 yards away, Toyosi was stabbed in the chest.

He was taken to Connolly Hospital in Blanchardstown but died around an hour later. Gardai sealed off the area and forensic officers combed the crime scene.

Officers say they are concerned about tensions in the area and the Garda Racial and Intercultural Office is working in the locality.