Two cars were stopped and searched in Clondalkin
One man remains in garda custody following a firearm seizure in Dublin on Friday.
Two men and a woman were released earlier without charge.
Three men and a woman were arrested in Clondalkin on Friday.
It was after two cars were stopped and searched on Monastery Gate Avenue - and two loaded revolvers were found.
The find was part of an operation targeting serious criminal activity in the Dublin region.
Gardaí say two of the men - aged 28 and 29 - and a 28-year-old woman were released from Clondalkin garda Station without charge.
A file is being prepared for the Director of Public Prosecutions (DPP).
A 26-year-old man remains in custody.