An investigation is under way into the discharge of a firearm and the discovery of a grenade in Ballyvolane, Cork city, shortly after midnight.
People living in nearby houses were evacuated while a controlled explosion was carried out in the early hours of this morning.
In a separate incident in Ballyvolane, a man in his 30s has been arrested after a suspected petrol bomb attack on a premises last night.
The incident occurred on the premises of Murphy's Rock Bar on Ballincollie Road at around 11pm.
Gardaí were alerted to what was described as "a difficult situation" at the pub involving a number of males.
It is understood that two customers were treated for minor injuries when outdoor decking was set on fire.
Cork City Fire Brigade were alerted to the incident and met by staff at the premises.
Second Officer Victor Shine said staff at the pub had mostly brought the fire under control when fire crews arrived, "so fire crews had to do some dampening down and deal with some smoke in the building and some minor damage".
Sinn Féin TD Thomas Gould said there was "fear and outrage" in many Cork city communities at escalating violent incidents
"It's not just Ballyvolane. There are gangs terrorising communities, and what we've seen over the weekend and over the past number of weeks and months is a number of shootings, a grenade attack, petrol bomb attacks, hit and runs and other violent incidents. What we have now is chaos," Mr Gould said.
He said "zero tolerance" and tougher sentences were needed going forward.
"We need the Minister for Justice to come to Cork to meet with the Garda Crime Division because right now, people feel nervous and are fearful in their homes and are fearful for their children while these gangs run riot.
And what we need is a zero tolerance approach to violence, and we need the minister and the gardaí to ensure that happens."
