Three men in their 20s are being held in Tallaght garda station in connection with a fatal stabbing last night.
A man in his 40s has been stabbed to death at Lower Bawn Lea Drive, in Jobstown shortly before 2.30 a.m. He was brought to Tallaght Hospital where he was pronounced dead on arrival.
The three men are being held under section four of the Criminal Justice Act.
Meanwhile, a man is in a critical condition after being stabbed in Cork city centre in the early hours of today.
The man, in his early 30s, was stabbed on Leitrim Street in north Cork at around 3 a.m.
He was taken to Cork University Hospital where he underwent emergency surgery.
In Belfast, a 39-year-old man has been arrested by police investigating a stabbing.
The victim, who was in his 40s, was found on the ground in the Ravenswood Park area of the city. He was taken to hospital but died shortly after getting there.