Armed Gardaí have carried out a raid in Crumlin, in south Dublin today.
It follows the arrest of four men on the M7 motorway earlier this week.
On Thursday, gardaí in Clonroche in Wexford received reports of four men holding up a garage armed with a gun.
During a follow-up operation, a car was intercepted by the Emergency Response Unit on the M7.
The vehicle was stopped at the 'Perpetual motion' landmark near Naas.
Four men in the car were arrested.
Armed gardaí conducted a search of a premise in Crumlin today in relation to the investigation.
So far they've found a sum of cash and seized a number of electronic devices.
The four men arrested on suspicion of the possession of a gun on Thursday are aged in their thirties, forties and fifties.
They're still being held at garda stations in Co. Wexford today.