GARDAÍ fired shots during two separate incidents in Cork overnight.
Shots were fired in the Mayfield area and in Fermoy.
A man has been arrested following the incidents, which took place over a half hour period, from around 11.45pm.
A number of shots were fired by gardaí during the course of the incident, and the matter has been referred to the Garda Síochána Ombudsman Commission, as is standard practice when a garda firearm is discharged.
Nobody was injured but a suspected firearm has been recovered.
The arrested man is being detained at Fermoy Garda Station for questioning.
Following the incident, the M8 motorway was closed in both directions between junctions 15 and 17, and diversions have are in place.
It is second incident when gardaí discharged a firearm in Cork in recent weeks.
One shot was discharged by a garda in May at a checkpoint in Mallow when two men were arrested under drugs legislation.
When a garda does open fire, the incident is always and immediately investigated by GSOC, the independent statutory body that provides oversight of policing in Ireland.
Such firearms incidents accounted for just 5% of referrals to the Garda Síochána Ombudsman Commission, according to the most recent report published by the body.