The woman stabbed in Dundalk has died in hospital.
A post-mortem will now take place at Our Lady of Lourdes Hospital in Drogheda.
Investigating Gardaí are appealing for witnesses or drivers who may have dash cam footage to contact the incident room at Dundalk Garda Station on 042-9388400, the Garda Confidential Line 1 800 666 111 or any Garda Station.
Earlier: Woman rushed to hospital after stabbing in Dundalk
A woman has been hospitalised after being stabbed in Dundalk.
The 31-year-old woman was stabbed at an apartment block in Linen Hall Street at 2.45pm this afternoon and she has been rushed to Our Lady Of Lourdes Hospital in Drogheda where her condition is described as "serious".
A 48-year-old man has been arrested in connection with the incident and is being held at Dundalk Garda Station.
There are reported to be eight garda cars and three ambulances at the scene which has been closed to traffic for a forensic examination.
A garda spokesperson said: “Gardaí at Dundalk Co Louth are investigating a stabbing incident which occurred at Linen Hall Street (Apartment Block) at approximately 2.45pm this afternoon, Tuesday September 18th.
#LOUTH Linenhall St in Dundalk closed due to incident. More here: https://t.co/ipFDM8svNY
— The AA Ireland (@aaroadwatch) September 18, 2018
"A female in her 20s was seriously injured, she was taken to Our Lady of Lourdes Hospital in Drogheda. A male in his 50s has been arrested in connection with this investigation and is currently detained under Section 4 at Dundalk Garda Station.