Over 100 gardai participated in searches of more than 40 houses in the Southill area of Limerick city yesterday seizing firearms, ammunition and drugs in the operation.
The national Garda air support unit and the Garda dog unit assisted up to local gardaí in the major search operation in which four firearms and some €5,000 worth of cannabis were seized.
The planned searches commenced at 2.30pm and by early evening at least four firearms including a handgun, a quantity of cannabis and a "significant" amount of ammunition had been seized, according to Garda sources.
A Garda spokesman confirmed that at least 40 properties and an area of open ground were searched during the operation.
A 37-year-old man arrested a short time after a gunman opened fire on two gardaí who were on patrol in an unmarked Garda car in the O'Malley Park area of Southill on Sunday night has been released without charge.
A senior Garda source said that yesterday's search operation had been planned prior to the shooting.