A man in his 20s has been arrested by gardaí investigating the two-car collision that claimed three lives in Co Louth early Saturday morning.
It is understood he is being detained under the provisions of section 4 of the Criminal Justice Act and was arrested on suspicion of dangerous driving causing death.
The detained man has an address in Northern Ireland.
Meanwhile, the post-mortems on the deceased will take place tomorrow.
The collision happened on the N1 at Carrickcarnan near the border at around 2.15am on Saturday morning.
It occurred on a dangerous weekend on Irish roads where seven people in total lost their lives.