Two men have been arrested after heroin, with an estimated street value of €8 million, was seized on a plane at Weston Airport.
It is the largest seizure of heroin in Ireland this year.
The light aircraft was searched and up to 60kg of vacuum-packed heroin was found in holdalls.
Two men in their 40s and 60s have been arrested. One man was arrested on the plane, and the other nearby.
They are being detained under drugs trafficking legislation at a garda station in Co Kildare and can be questioned for up to seven days.
The light aircraft has also been seized and gardaí are now tracing its flightpath.
Gardaí say the seizure follows an intelligence-led operation involving the Drugs and Organised Crime Bureau and Revenue Customs.
Detectives say the drugs were sourced by a family-based west Dublin gang with links to the Kinahan Organised Crime Group and were for distribution in Dublin and around the country.
The gang had been under surveillance and the seizure was made around midday.
Following the operation, Assistant Garda Commissioner, Organised and Serious Crime Justin Kelly described the seizure as "hugely significant".
He said: "The importance of disrupting criminal networks supplying this type of drug into our communities has been reinforced by the recent wave of overdoses in Dublin city centre.
"Worldwide, law enforcement agencies are seeing an increasing use of general aviation (non-commercial flights) to smuggle drugs."
"This operation shows the importance of multi-agency co-operation, in this case between An Garda Síochána, Irish Customs and the Maritime Analysis and Operations Centre in Lisbon, Portugal," he added.
