Gardai have seized €900,000 worth of drugs as part of a major operation which targeted gangs operating in Co Kildare and west Dublin.
Last night three men remained in custody at Clondalkin Garda Station after their arrest in the Newlands Cross area of the capital on Wednesday evening.
The trio who are aged 40, 34 and 22, were arrested when two cars were stopped and searched in the locality by armed detectives from the Drugs and Organised Crime Bureau who were backing up officers from the Kildare garda division.
None of the arrested men are known as major players on the gangland scene and they have separate addresses in Clondalkin as well as Newbridge and Rathangan in Co Kildare.
Searches were still continuing last night as part of the investigation after officers stopped a VW Passat and a Chevrolet at a around 7.30pm on Wednesday.
Gardai initially discovered four kilos of heroin with a street value of around €600,000 and arrested the three suspects.
A further €300,000 worth of other drugs were discovered in additional searches.
"A number of follow-up searches were conducted in the Kildare and Dublin areas resulting in quantities of cocaine and cannabis herb also being recovered," a garda spokesman said.
"At this time, controlled drugs with an estimated street value of €900,000 have been seized in this operation. Investigations are ongoing."
Sources say that the major bust had been part of a lengthy surveillance operation which primarily has been targeting a Kildare-based drugs mob.
It was one of the biggest busts of the year and the most significant since officers seized around €3m worth of heroin and cocaine and a major weapons haul in Tallaght in October.
However, this week's bust is not linked to that investigation, and sources say that it is now expected that there will be a major shortage of heroin in the Kildare market over the coming weeks.
The seizure is one of a number of high-profile successes that the garda bureau has had since the amalgamation of the Garda National Drugs Unit and Organised Crime Unit earlier this year.