A cyclist in his 50s and a pedestrian in her 20s have died in separate road incidents.
Gardaí said the man in his 50s was found in the cycle lane on Pearse Road, Sligo town, shortly after 11.30pm last night.
He was taken to Sligo University Hospital where he was later pronounced dead. Diversions are in place while a forensic examination is carried out.
Meanwhile, a young woman has died following a road collision in Co Fermanagh.
The 20-year-old pedestrian was involved in the incident on the Belfast Road in Lisbellaw at around 5.50pm yesterday.
A PSNI spokesperson said a 25-year-old man was arrested and remained in police custody this morning.
Gardaí are appealing for witnesses to the Sligo incident to come forward, and are asking anyone who may have information, or dashcam footage from the area between 11.30pm and midnight to make it available to them.
Anyone with information can contact Sligo Garda Station on 071 9157000, the Garda Confidential Line on 1800 666 111, or any garda station.
PSNI officers have also appealed to anyone who witnessed the Fermanagh collision or who may have captured dash-cam or other footage in the area at the time to get in touch by calling 101, quoting reference 1600 13/12/23.
