Three children and a woman in her 30s have been injured after a fire broke out at a block of flats in Inchicore in Dublin last night.
Emergency services were called to scene at around 11.20pm and fire fighters battled the blaze for several hours.
Two of the children, aged eight and 13, were taken to Crumlin Children's Hospital where one is thought to be in a critical condition.
The third child, a seven-year-old boy, is being treated at Temple Street Hospital, while the woman remains in a serious condition at St James.
Gardaí have sealed off the flat and have asked anyone with information to contact them at Kilmainham Garda Station on (01) 666 9700.
A man has been arrested by Gardaí and members of the Special Crime Task Force during an operation in Dublin.
A firearm was seized during the arrest, which happened in Inchicore this afternoon.
Shortly before 3pm, a van failed to stop for Gardaí during an operation on Kylemore Way.
The van was stopped and a firearm and silencer were recovered after a search of the vehicle.
A man in his late 20s arrested at the scene after a number of shots were fired by Gardaí during the incident.
No one was injured during the arrest.
A second vehicle thought to be involved in the incident fled from the scene.
Investigating Gardaí have preserved the scene for forensic examination.