A man has been arrested as part of an ongoing investigation into the activities of dissident Republicans.
The suspect, in his 20s, was detained by gardai from the Special Detective Unit in Dublin.
A firearm was also seized in the operation in the Coolock area at 6.30pm on Monday.
The man is being held at Blanchardstown Garda Station under Section 30 of the Offences Against the State Act.
Elsewhere, two men were arrested over the discovery of a pipebomb in a car at Cappa Beg, Barefield, Ennis, in Co Clare.
An Army bomb disposal team was called to the scene at about 1am to make safe the improvised explosive device (IED).
Two suspects, in their early 20s, are being detained at Ennis Garda Station under Section 30 of the Offences Against The State Act.
The area has been technically examined and is now clear.
It was the 108th call-out of defence forces bomb disposal teams so far this year and the 43rd viable IED rendered safe.