Four people have died in separate road accidents.
A 22-year-old man has died following a road crash involving two cars that happened between Milltown and Killorglin, Co Kerry.
The dead man was the driver of a car which was travelling towards Kilorglin when it was involved in a collision with a car driving in the opposite direction.
A passenger in that car and two people in the other car have been taken to hospital in Tralee.
The road between Milltown and Killorglin is closed and will still closed until midday tomorrow to allow gardaí to conduct a technical examination of the scene.
The 19-year-old man who was killed in a two-car collision on the main Abbeyfeale to Castleisland Road has been named as Ray Stryker.
Mr Stryker was a passenger in a Peugeot car which was involved in a crash with a four wheel drive.
The male driver of the car is in a serious but stable condition at Kerry General Hospital in Tralee.
The driver of the other vehicle was not seriously injured. The man who died in an accident on the N9 at Kilfane, Thomastown, Co Kilkenny has been named as Patrick Hayes, aged 20, from Market Street, Thomastown.
Gardaí are appealing for witnesses to contact them on 056 7754150, the Garda confidential line on 1800 666 111, or any Garda station.
In Northern Ireland, a man was killed and two people were seriously injured in an accident on the Portadown road outside Armagh.
