In Co Limerick, a man in his 20s was killed after the car he was driving collided with a tree on the N21 at Cummeen, Adare. The single-vehicle collision happened at approximately 2.40am.
The driver was pronounced dead at the scene and his remains were later taken to the mortuary at University Hospital Limerick. A post-mortem examination will be carried out.
Two passengers were also in the vehicle. A man in his 20s was taken to University Hospital Limerick and remains in a critical condition, while a second passenger, a man in his late teens, suffered injuries that are not considered life-threatening.
The N21 was closed in the area to allow Garda Forensic Collision Investigators to examine the scene, with diversions put in place.
Gardaí are appealing to anyone who travelled along the N21 at Cummeen between 2.15am and 2.45am and may have witnessed the incident or captured footage on a dash-cam or other camera.
Meanwhile, a separate fatal collision occurred in Athboy, Co Meath.
A man in his 50s died after the car he was driving crashed into a premises on Connaught Street at around 2am. He was the sole occupant of the vehicle and was pronounced dead at the scene.
His body was taken to the mortuary at Our Lady's Hospital in Navan, where a post-mortem examination will take place.
Connaught Street was also closed while Garda Forensic Collision Investigators carried out an examination, with local diversions introduced.
Gardaí are seeking witnesses who were in the Connaught Street area between approximately 1.45am and 2.15am, particularly anyone who may have relevant camera or dash-cam footage.
Anyone with information about either collision is asked to contact the relevant Garda station. Information can also be provided through the Garda Confidential Line on 1800 666 111.
