A man in his 40s has died after two cars collided on the N22 near Crookstown between Macroom and Ballincollig in Co Cork at around 4 p.m.
A man and a woman, who were travelling in the other car, were seriously injured. The pair were brought to Cork Regional Hospital.
Earlier this morning, three people died in a crash in Co Antrim when a sports car hit another car. RUC officers who came upon the scene were attacked by a crowd.
The incident happened at Templepatrick, Co Antrim, on a stretch of road between the Dunadry Inn and the Twelfth Milestone roundabout at 1.40 a.m.
The sports car was seen by an RUC patrol driving erratically on a nearby roundabout on the Ballyrobin road a short time earlier.
The RUC patrol pursued the car but came upon the crash a short time later.
While officers tended to the injured a crowd gathered and assaulted two officers, an RUC spokeswoman said.
Four other people including the occupants of the car are being treated in hospital.
The RUC is appealling for witesses and has referred the matter to the police Ombudsman.
Meanwhile a teenager died this morning after his car struck a lampost at 2.30 a.m. in Dundonald, Belfast.