Garda Commissioner Fachtna Murphy has briefed the Minister for Justice on an incident in Lucan in which gardaí foiled an attempted raid on a cash-in-transit van.
A 27-year-old man with an address at Sheriff Street in Dublin City, died in hospital after he was shot by gardaí.
The incident happened just after 12pm today during an operation by the Organised Crime Unit on the Foxborough Road.
A second man is understood to have serious injuries and is being treated in hospital.
Gardaí later arrested three men in the Neilstown area after they stopped what they believed was a get-away vehicle.
A fourth man has also been arrested by gardaí.
At least one sawn-off shotgun has been recovered, along with a stolen car.
The Garda Síochána Ombudsman Commission has confirmed that it is now investigating the incident.
Dermot Ahern said that, while the loss of any life was to be regretted, he had no doubt the gardaí had the full support of the community in taking whatever action was necessary when confronted by armed gangs.
Minister Ahern said: ‘Today's incident is a reminder of the dangers faced by members of An Garda Síochána in carrying out their duties and their courage in confronting those dangers’.